CVE-2026-63887

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63887", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.018Z", "datePublished": "2026-07-19T14:55:00.114Z", "dateUpdated": "2026-10-19T20:17:54.668Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:36:56.451Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf\n\niscsi_encode_text_output() concatenates \"key=value\\0\" records into\nlogin->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer\nallocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call\nsites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check\nthe remaining buffer capacity:\n\n\t*length += sprintf(output_buf, \"%s=%s\", er->key, er->value);\n\t*length += 1;\n\toutput_buf = textbuf + *length;\n\nThe 8192-byte ceiling at iscsi_target_check_login_request() bounds the\n*input* Login PDU payload, but a single PDU can carry up to 2048 minimal\nfour-byte \"a=b\\0\" pairs, each unknown key expanding to a 16-byte\n\"a=NotUnderstood\\0\" output record via iscsi_add_notunderstood_response().\n2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB\nheap overrun in the kmalloc-8k slab.\n\nThe fix introduces a static iscsi_encode_text_record() helper that uses\nsnprintf() with a per-call bounds check against the remaining buffer,\nand threads a u32 textbuf_size parameter through\niscsi_encode_text_output(). Both call sites in\niscsi_target_handle_csg_zero() (PHASE_SECURITY) and\niscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass\nMAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls\niscsi_release_extra_responses() to drop queued records, and returns -1;\nboth caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR /\nISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning,\nso the initiator sees an explicit failed-login response rather than a\nsilent connection drop. (Prior to this patch only the PHASE_OPERATIONAL\ncaller did that; the PHASE_SECURITY caller is converted to the same\nshape.)"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The Linux iSCSI target (LIO) is an in-kernel SCSI target that accepts remote TCP connections on the iSCSI portal (typically port 3260); crafted Login PDUs reach the vulnerable encoder via the normal network receive and login-negotiation path.\nAC:L - Once an iSCSI target portal is reachable, an attacker can reliably trigger the overflow by sending a single Login PDU packed with unknown key=value pairs; no races or victim-dependent timing are required.\nPR:N - The heap overflow occurs during login negotiation before iSCSI authentication completes; a discovery-session login requires only InitiatorName and SessionType with no credentials, initiator ACL, or local privileges.\nUI:N - Exploitation requires only network packets sent by the attacker; no action from a legitimate user or administrator is needed beyond the target already exposing its iSCSI portal.\nS:U - The corruption is confined to kernel heap memory in the iSCSI target/login context and does not cross a VM, container, or IOMMU security boundary by itself.\nC:H - A ~24 KiB out-of-bounds write into the kmalloc-8k slab can corrupt adjacent kernel objects and be leveraged for arbitrary memory disclosure, not merely a bounded leak.\nI:H - The unbounded sprintf heap overrun is a large out-of-bounds write that can corrupt adjacent heap metadata or objects to achieve arbitrary kernel memory modification and potential code execution.\nA:H - Corrupting kmalloc-8k heap objects during login response encoding can cause kernel oops, BUG, or panic, and the attack can be repeated against an exposed iSCSI target."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/target/iscsi/iscsi_target_nego.c", "drivers/target/iscsi/iscsi_target_parameters.c", "drivers/target/iscsi/iscsi_target_parameters.h"], "versions": [{"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "cb84e974fb172bc71386289f37b78ea679410b39", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "b19382dfc6e7dee6d3859ba44b6ca29e97a51627", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "efe633e600a0ac68357206fede21b1ac8178f3b8", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "4e9f0c4a645c995bc75c06c7b3644254ffb4c76b", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "30bf335e8fe170322080ee001f05ca29c50680b3", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "594a40360012ce5f94c715d5e3b20fa3af7d525a", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "26e4a304b7e6f1338c675d527608d32549c091db", "status": "affected", "versionType": "git"}, {"version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "bf33e01f88388c43e285492a63e539df6ffed64c", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/target/iscsi/iscsi_target_nego.c", "drivers/target/iscsi/iscsi_target_parameters.c", "drivers/target/iscsi/iscsi_target_parameters.h"], "versions": [{"version": "3.1", "status": "affected"}, {"version": "0", "lessThan": "3.1", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "5.10.259"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "5.15.210"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.1.176"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.6.143"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.12.93"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.18.35"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.0.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/cb84e974fb172bc71386289f37b78ea679410b39"}, {"url": "https://git.kernel.org/stable/c/b19382dfc6e7dee6d3859ba44b6ca29e97a51627"}, {"url": "https://git.kernel.org/stable/c/efe633e600a0ac68357206fede21b1ac8178f3b8"}, {"url": "https://git.kernel.org/stable/c/4e9f0c4a645c995bc75c06c7b3644254ffb4c76b"}, {"url": "https://git.kernel.org/stable/c/30bf335e8fe170322080ee001f05ca29c50680b3"}, {"url": "https://git.kernel.org/stable/c/594a40360012ce5f94c715d5e3b20fa3af7d525a"}, {"url": "https://git.kernel.org/stable/c/26e4a304b7e6f1338c675d527608d32549c091db"}, {"url": "https://git.kernel.org/stable/c/bf33e01f88388c43e285492a63e539df6ffed64c"}], "title": "scsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-63887", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:32:57.099055Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-122", "description": "CWE-122 Heap-based Buffer Overflow"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-19T20:17:54.668Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-63887", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:32:57.099055Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-122", "description": "CWE-122 Heap-based Buffer Overflow"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T15:32:57.678Z"}}], "cna": {"title": "scsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 9.8, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - The Linux iSCSI target (LIO) is an in-kernel SCSI target that accepts remote TCP connections on the iSCSI portal (typically port 3260); crafted Login PDUs reach the vulnerable encoder via the normal network receive and login-negotiation path.\nAC:L - Once an iSCSI target portal is reachable, an attacker can reliably trigger the overflow by sending a single Login PDU packed with unknown key=value pairs; no races or victim-dependent timing are required.\nPR:N - The heap overflow occurs during login negotiation before iSCSI authentication completes; a discovery-session login requires only InitiatorName and SessionType with no credentials, initiator ACL, or local privileges.\nUI:N - Exploitation requires only network packets sent by the attacker; no action from a legitimate user or administrator is needed beyond the target already exposing its iSCSI portal.\nS:U - The corruption is confined to kernel heap memory in the iSCSI target/login context and does not cross a VM, container, or IOMMU security boundary by itself.\nC:H - A ~24 KiB out-of-bounds write into the kmalloc-8k slab can corrupt adjacent kernel objects and be leveraged for arbitrary memory disclosure, not merely a bounded leak.\nI:H - The unbounded sprintf heap overrun is a large out-of-bounds write that can corrupt adjacent heap metadata or objects to achieve arbitrary kernel memory modification and potential code execution.\nA:H - Corrupting kmalloc-8k heap objects during login response encoding can cause kernel oops, BUG, or panic, and the attack can be repeated against an exposed iSCSI target."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "cb84e974fb172bc71386289f37b78ea679410b39", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "b19382dfc6e7dee6d3859ba44b6ca29e97a51627", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "efe633e600a0ac68357206fede21b1ac8178f3b8", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "4e9f0c4a645c995bc75c06c7b3644254ffb4c76b", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "30bf335e8fe170322080ee001f05ca29c50680b3", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "594a40360012ce5f94c715d5e3b20fa3af7d525a", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "26e4a304b7e6f1338c675d527608d32549c091db", "versionType": "git"}, {"status": "affected", "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "bf33e01f88388c43e285492a63e539df6ffed64c", "versionType": "git"}], "programFiles": ["drivers/target/iscsi/iscsi_target_nego.c", "drivers/target/iscsi/iscsi_target_parameters.c", "drivers/target/iscsi/iscsi_target_parameters.h"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3.1"}, {"status": "unaffected", "version": "0", "lessThan": "3.1", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.259", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.210", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.176", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.143", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.93", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.35", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.0.12", "versionType": "semver", "lessThanOrEqual": "7.0.*"}, {"status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/target/iscsi/iscsi_target_nego.c", "drivers/target/iscsi/iscsi_target_parameters.c", "drivers/target/iscsi/iscsi_target_parameters.h"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/cb84e974fb172bc71386289f37b78ea679410b39"}, {"url": "https://git.kernel.org/stable/c/b19382dfc6e7dee6d3859ba44b6ca29e97a51627"}, {"url": "https://git.kernel.org/stable/c/efe633e600a0ac68357206fede21b1ac8178f3b8"}, {"url": "https://git.kernel.org/stable/c/4e9f0c4a645c995bc75c06c7b3644254ffb4c76b"}, {"url": "https://git.kernel.org/stable/c/30bf335e8fe170322080ee001f05ca29c50680b3"}, {"url": "https://git.kernel.org/stable/c/594a40360012ce5f94c715d5e3b20fa3af7d525a"}, {"url": "https://git.kernel.org/stable/c/26e4a304b7e6f1338c675d527608d32549c091db"}, {"url": "https://git.kernel.org/stable/c/bf33e01f88388c43e285492a63e539df6ffed64c"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf\n\niscsi_encode_text_output() concatenates \"key=value\\0\" records into\nlogin->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer\nallocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call\nsites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check\nthe remaining buffer capacity:\n\n\t*length += sprintf(output_buf, \"%s=%s\", er->key, er->value);\n\t*length += 1;\n\toutput_buf = textbuf + *length;\n\nThe 8192-byte ceiling at iscsi_target_check_login_request() bounds the\n*input* Login PDU payload, but a single PDU can carry up to 2048 minimal\nfour-byte \"a=b\\0\" pairs, each unknown key expanding to a 16-byte\n\"a=NotUnderstood\\0\" output record via iscsi_add_notunderstood_response().\n2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB\nheap overrun in the kmalloc-8k slab.\n\nThe fix introduces a static iscsi_encode_text_record() helper that uses\nsnprintf() with a per-call bounds check against the remaining buffer,\nand threads a u32 textbuf_size parameter through\niscsi_encode_text_output(). Both call sites in\niscsi_target_handle_csg_zero() (PHASE_SECURITY) and\niscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass\nMAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls\niscsi_release_extra_responses() to drop queued records, and returns -1;\nboth caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR /\nISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning,\nso the initiator sees an explicit failed-login response rather than a\nsilent connection drop. (Prior to this patch only the PHASE_OPERATIONAL\ncaller did that; the PHASE_SECURITY caller is converted to the same\nshape.)"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.259", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.210", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.176", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.143", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.93", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.35", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.0.12", "versionStartIncluding": "3.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1", "versionStartIncluding": "3.1"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:36:56.451Z"}}}, "cveMetadata": {"cveId": "CVE-2026-63887", "state": "PUBLISHED", "dateUpdated": "2026-10-19T20:17:54.668Z", "dateReserved": "2026-07-19T07:54:57.018Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-07-19T14:55:00.114Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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"status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.259", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.210", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.176", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.143", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.93", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.35", "versionType": "semver"}, {"lessThanOrEqual": "7.0.*", "status": "unaffected", "version": "7.0.12", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": 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"6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "0FCCB23A-7629-4386-93B6-B119237C4382", "versionEndExcluding": "6.18.35", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "9161A938-0FA8-44BC-95FE-C5A271601AB3", "versionEndExcluding": "7.0.12", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*", "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*", "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*", "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*", "matchCriteriaId": "E5910A9D-F60A-409A-B486-FE66BFEBA9B9", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*", "matchCriteriaId": "81DFF19E-9CF8-49C6-8C36-1E4038622933", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf\n\niscsi_encode_text_output() concatenates \"key=value\\0\" records into\nlogin->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer\nallocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call\nsites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check\nthe remaining buffer capacity:\n\n\t*length += sprintf(output_buf, \"%s=%s\", er->key, er->value);\n\t*length += 1;\n\toutput_buf = textbuf + *length;\n\nThe 8192-byte ceiling at iscsi_target_check_login_request() bounds the\n*input* Login PDU payload, but a single PDU can carry up to 2048 minimal\nfour-byte \"a=b\\0\" pairs, each unknown key expanding to a 16-byte\n\"a=NotUnderstood\\0\" output record via iscsi_add_notunderstood_response().\n2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB\nheap overrun in the kmalloc-8k slab.\n\nThe fix introduces a static iscsi_encode_text_record() helper that uses\nsnprintf() with a per-call bounds check against the remaining buffer,\nand threads a u32 textbuf_size parameter through\niscsi_encode_text_output(). Both call sites in\niscsi_target_handle_csg_zero() (PHASE_SECURITY) and\niscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass\nMAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls\niscsi_release_extra_responses() to drop queued records, and returns -1;\nboth caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR /\nISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning,\nso the initiator sees an explicit failed-login response rather than a\nsilent connection drop. (Prior to this patch only the PHASE_OPERATIONAL\ncaller did that; the PHASE_SECURITY caller is converted to the same\nshape.)"}], "id": "CVE-2026-63887", "lastModified": "2026-10-22T14:33:17.540", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-63887", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T15:32:57.099055Z", "version": "2.0.3"}}]}, "published": "2026-07-19T16:17:05.853", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/26e4a304b7e6f1338c675d527608d32549c091db"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/30bf335e8fe170322080ee001f05ca29c50680b3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4e9f0c4a645c995bc75c06c7b3644254ffb4c76b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/594a40360012ce5f94c715d5e3b20fa3af7d525a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b19382dfc6e7dee6d3859ba44b6ca29e97a51627"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/bf33e01f88388c43e285492a63e539df6ffed64c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/cb84e974fb172bc71386289f37b78ea679410b39"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/efe633e600a0ac68357206fede21b1ac8178f3b8"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-120"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-122"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: scsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf", "id": "2502447", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502447"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-120", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nscsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf\niscsi_encode_text_output() concatenates \"key=value\\0\" records into\nlogin->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer\nallocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call\nsites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check\nthe remaining buffer capacity:\n*length += sprintf(output_buf, \"%s=%s\", er->key, er->value);\n*length += 1;\noutput_buf = textbuf + *length;\nThe 8192-byte ceiling at iscsi_target_check_login_request() bounds the\n*input* Login PDU payload, but a single PDU can carry up to 2048 minimal\nfour-byte \"a=b\\0\" pairs, each unknown key expanding to a 16-byte\n\"a=NotUnderstood\\0\" output record via iscsi_add_notunderstood_response().\n2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB\nheap overrun in the kmalloc-8k slab.\nThe fix introduces a static iscsi_encode_text_record() helper that uses\nsnprintf() with a per-call bounds check against the remaining buffer,\nand threads a u32 textbuf_size parameter through\niscsi_encode_text_output(). Both call sites in\niscsi_target_handle_csg_zero() (PHASE_SECURITY) and\niscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass\nMAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls\niscsi_release_extra_responses() to drop queued records, and returns -1;\nboth caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR /\nISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning,\nso the initiator sees an explicit failed-login response rather than a\nsilent connection drop. (Prior to this patch only the PHASE_OPERATIONAL\ncaller did that; the PHASE_SECURITY caller is converted to the same\nshape.)", "A flaw was found in the Linux kernel's iSCSI (Internet Small Computer System Interface) target functionality. This vulnerability, a heap overrun, occurs because the iscsi_encode_text_output() function does not properly check buffer capacity when processing login requests. A remote attacker could exploit this by sending a specially crafted login request with numerous key-value pairs, leading to a memory corruption issue and potentially a denial of service (DoS) on the system."], "name": "CVE-2026-63887", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63887\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63887\nhttps://lore.kernel.org/linux-cve-announce/2026071940-CVE-2026-63887-cf4b@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,cb84e974fb172bc71386289f37b78ea679410b39)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,b19382dfc6e7dee6d3859ba44b6ca29e97a51627)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,efe633e600a0ac68357206fede21b1ac8178f3b8)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,4e9f0c4a645c995bc75c06c7b3644254ffb4c76b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,30bf335e8fe170322080ee001f05ca29c50680b3)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,594a40360012ce5f94c715d5e3b20fa3af7d525a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,26e4a304b7e6f1338c675d527608d32549c091db)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[e48354ce078c079996f89d715dfa44814b4eba01,bf33e01f88388c43e285492a63e539df6ffed64c)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "3.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.1)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.259,5.11.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.210,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.176,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.143,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.93,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.35,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T10:00:04.564679+00:00", "updated": "2026-10-20T14:00:16.589502+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}