CVE-2026-99110

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-99110", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.392Z", "datePublished": "2026-10-28T10:34:28.239Z", "dateUpdated": "2026-10-31T12:43:03.377Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-31T12:43:03.377Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n 4 + (count * 8) // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n 6 + (count * 10) // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL. Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX)."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - setxattr(2) on system.posix_acl_access/default flows through do_set_acl() \u2192 set_posix_acl() \u2192 cifs_set_acl() \u2192 patched cifs_do_set_acl(); the oversized ACL originates in the local xattr, while SMB_COM_TRANSACTION2 is only an outbound request.\nAC:H - The copy is deterministic once reached, but it requires default-off CONFIG_CIFS_POSIX, an SMB1 mount, and server negotiation of CIFS_UNIX_POSIX_ACL_CAP to set SB_POSIXACL. An unprivileged local attacker cannot create that mount or capability state.\nPR:L - set_posix_acl() gates the path with inode_owner_or_capable(), so an ordinary user who owns a file on the mounted share can submit the ACL without capabilities; on a non-multiuser mount cifs_sb_tlink() simply reuses the master tcon.\nUI:N - The attacker directly invokes setxattr() or fsetxattr() on their CIFS inode, causing cifs_set_acl() to run without any separate victim action after the qualifying mount exists.\nS:U - posix_acl_to_cifs() overwrites the client kernel's cifs_request slab, and any resulting kernel compromise remains within the same host security authority rather than crossing a VM, IOMMU, or sandbox boundary.\nC:H - cifs_init_ace() emits attacker-shaped 10-byte tag, permission, and uid/gid records past the cifs_request object; with the supported 8KiB CIFSMaxBufSize, the overflow reaches neighboring request objects. This controllable slab corruption can be groomed into reuse or overlap and kernel-memory disclosure.\nI:H - posix_acl_to_cifs() writes a multi-kilobyte out-of-bounds stream whose ACE tags, permissions, and 32-bit uid/gid values are caller-selected; corrupting adjacent request or allocator state provides heap-write and control-flow-hijack potential.\nA:H - With default CIFSMaxBufSize=16384, 2047 valid entries pass cifs_set_acl()'s 16380-byte check but make posix_acl_to_cifs() write 20476 bytes, nearly 4KiB beyond the 16588-byte allocation before SendReceive() rejects the frame. Repeated calls can oops or panic the kernel."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/cifssmb.c"], "versions": [{"version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "68652afb9b9adf70125971abee9b95341e042249", "status": "affected", "versionType": "git"}, {"version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "9312a00215602ba028495ef3fa00fb84af0478e0", "status": "affected", "versionType": "git"}, {"version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "d96f3365ce61c5f39602955af43c8174548dee98", "status": "affected", "versionType": "git"}, {"version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "596b4062e6c75bdd85a7f2b7f2087a872dc420ac", "status": "affected", "versionType": "git"}, {"version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "1dac61e2c29d1a71784604b48cf3b1234a65ec29", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/cifssmb.c"], "versions": [{"version": "6.2", "status": "affected"}, {"version": "0", "lessThan": "6.2", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.59", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.13", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "6.2", "versionEndExcluding": "6.6.161"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.18.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.2.13"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249"}, {"url": "https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0"}, {"url": "https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98"}, {"url": "https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac"}, {"url": "https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29"}], "title": "smb: client: fix heap overflow in cifs_do_set_acl()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/client/cifssmb.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "68652afb9b9adf70125971abee9b95341e042249", "status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "versionType": "git"}, {"lessThan": "9312a00215602ba028495ef3fa00fb84af0478e0", "status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "versionType": "git"}, {"lessThan": "d96f3365ce61c5f39602955af43c8174548dee98", "status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "versionType": "git"}, {"lessThan": "596b4062e6c75bdd85a7f2b7f2087a872dc420ac", "status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "versionType": "git"}, {"lessThan": "1dac61e2c29d1a71784604b48cf3b1234a65ec29", "status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/client/cifssmb.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.2"}, {"lessThan": "6.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.161", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.115", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.59", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.13", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n 4 + (count * 8) // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n 6 + (count * 10) // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL. Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX)."}], "id": "CVE-2026-99110", "lastModified": "2026-10-31T13:17:55.833", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.0, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.0, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-10-28T11:17:30.410", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: smb: client: fix heap overflow in cifs_do_set_acl()", "id": "2562659", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562659"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nsmb: client: fix heap overflow in cifs_do_set_acl()\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n4 + (count * 8) // 4-byte header + 8 bytes per ACE\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n6 + (count * 10) // 6-byte header + 10 bytes per ACE\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL. Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX).", "A flaw was found in the Linux kernel's Common Internet File System (CIFS) client. When converting a POSIX Access Control List (ACL) to the network wire format, the kernel verifies the ACL against an extended attribute size calculation instead of the larger network format size, leading to a heap-based buffer overflow. A local user can exploit this vulnerability by setting an access control list on a mounted share to achieve privilege escalation, execute arbitrary code, or crash the system, causing a Denial of Service (DoS)."], "name": "CVE-2026-99110", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not 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": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-28T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-99110\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-99110\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99110.mbox"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,d96f3365ce61c5f39602955af43c8174548dee98)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,596b4062e6c75bdd85a7f2b7f2087a872dc420ac)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,1dac61e2c29d1a71784604b48cf3b1234a65ec29)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.59,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.13,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,d96f3365ce61c5f39602955af43c8174548dee98)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,596b4062e6c75bdd85a7f2b7f2087a872dc420ac)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[dc1af4c4b4721abfa07b351063825acc7e69cc66,1dac61e2c29d1a71784604b48cf3b1234a65ec29)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"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": "6.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.59,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.13,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-28T12:00:22.515414+00:00", "updated": "2026-10-31T15:00:09.068367+00:00", "vendors": ["linux", "linux$PRODUCT$linux", "linux$PRODUCT$linux_kernel"]}