CVE-2026-90176

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-90176", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.791Z", "datePublished": "2026-09-17T16:07:02.433Z", "dateUpdated": "2026-10-19T08:59:13.411Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:59:13.411Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: Do not skip lock checks for single-byte ranges\n\ncheck_lock_range() uses inclusive ranges. Its callers pass the end\noffset as start + length - 1, so start == end represents a valid\nsingle-byte range rather than an empty range.\n\nThe start == end shortcut therefore skips mandatory byte-range lock\nchecks for one-byte reads, writes, copychunk operations and one-byte\ntruncate ranges. A conflicting lock covering that byte is not checked\nand the operation is allowed to proceed.\n\nRemove the shortcut. The truncate size == inode->i_size case is already\nhandled by only calling check_lock_range() when the new size differs\nfrom the current file size."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 8.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - The skip is driven by attacker-controlled range length in SMB2 PDUs: smb2_read()/smb2_write() pass Length==1 into ksmbd_vfs_read/write, set_end_of_file_info() passes a 1-byte size change to ksmbd_vfs_truncate(), and FSCTL_SRV_COPYCHUNK Length==1 reaches ksmbd_vfs_copy_file_ranges(); those messages arrive on the ksmbd TCP connection in ksmbd_conn_handler_loop().\nAC:L - Callers pass an inclusive end of start+length-1, so Length==1 makes start==end and the shortcut in check_lock_range() returns 0 before walking ctx->flc_posix; the attacker sets Length, Offset, EndOfFile, or COPYCHUNK Length in the PDU, and the skip is deterministic with no race or uncontrollable layout.\nPR:L - smb2_check_user_session() requires SMB2_SESSION_VALID before SMB2_READ/WRITE/SET_INFO/IOCTL, smb2_get_ksmbd_tcon() requires a tree connect, and the handlers resolve a fid via ksmbd_lookup_fd_slow(); this is not negotiate or session-setup, so an authenticated SMB share user is required.\nUI:N - The attacker, holding their own session, tree connect, and open handle, sends the one-byte SMB2 READ, WRITE, SET_INFO FILE_END_OF_FILE_INFORMATION, or FSCTL_SRV_COPYCHUNK; no other user must mount media or confirm an action.\nS:U - Bypassing check_lock_range() only allows this ksmbd worker to read or write host file bytes that conflicting FL_POSIX locks on flc_posix should have denied; there is no VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - ksmbd_vfs_read() and the COPYCHUNK source check skip exclusive F_WRLCK locks belonging to another filp when start==end, so kernel_read() returns that byte; repeating SMB2 READ at chosen offsets discloses every exclusively locked byte of a file the attacker can open.\nI:H - ksmbd_vfs_write(), ksmbd_vfs_truncate() for size==i_size\u00b11, and COPYCHUNK dest checks likewise skip conflicting F_RDLCK/F_WRLCK, so kernel_write() and vfs_truncate() can overwrite locked bytes or change size by one at attacker-chosen offsets.\nA:N - When the shortcut hits, check_lock_range() returns 0 and the existing kernel_read/kernel_write/vfs_truncate path runs normally; the bug does not NULL-deref, BUG, deadlock, or panic, and the ksmbd worker keeps serving."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/vfs.c"], "versions": [{"version": "52fcbb92e0d3acfd1448b2a43b6595d540da5295", "lessThan": "a89cc145832e81c32199d4ca2e1ea8bd51ed601d", "status": "affected", "versionType": "git"}, {"version": "da29cd197246c85c0473259f1cad897d9d28faea", "lessThan": "993e0158331d37c04da18efe551b5e1e35fb3078", "status": "affected", "versionType": "git"}, {"version": "a6f4cfa3783804336491e0edcb250c25f9b59d33", "lessThan": "f751d6e39d4c937c45f8fedc66699aa7d2d52288", "status": "affected", "versionType": "git"}, {"version": "571204e4758a528fbd67330bd4b0dfbdafb33dd8", "lessThan": "84c2d8e807ac489f5c91769293fb15dfdae8bae8", "status": "affected", "versionType": "git"}, {"version": "5d510ac31626ed157d2182149559430350cf2104", "lessThan": "07a9e289ff7edcc004f58952405f8a65c4e37512", "status": "affected", "versionType": "git"}, {"version": "5d510ac31626ed157d2182149559430350cf2104", "lessThan": "d40c24634fe077a0dc91fd11fccf44ce12b454d5", "status": "affected", "versionType": "git"}, {"version": "6.1.160", "lessThan": "6.1.188", "status": "affected", "versionType": "semver"}, {"version": "6.6.120", "lessThan": "6.6.157", "status": "affected", "versionType": "semver"}, {"version": "6.12.64", "lessThan": "6.12.110", "status": "affected", "versionType": "semver"}, {"version": "6.18.3", "lessThan": "6.18.52", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/vfs.c"], "versions": [{"version": "6.19", "status": "affected"}, {"version": "0", "lessThan": "6.19", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.6", "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": "6.1.160", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.120", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.64", "versionEndExcluding": "6.12.110"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.3", "versionEndExcluding": "6.18.52"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "7.2.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a89cc145832e81c32199d4ca2e1ea8bd51ed601d"}, {"url": "https://git.kernel.org/stable/c/993e0158331d37c04da18efe551b5e1e35fb3078"}, {"url": "https://git.kernel.org/stable/c/f751d6e39d4c937c45f8fedc66699aa7d2d52288"}, {"url": "https://git.kernel.org/stable/c/84c2d8e807ac489f5c91769293fb15dfdae8bae8"}, {"url": "https://git.kernel.org/stable/c/07a9e289ff7edcc004f58952405f8a65c4e37512"}, {"url": "https://git.kernel.org/stable/c/d40c24634fe077a0dc91fd11fccf44ce12b454d5"}], "title": "ksmbd: Do not skip lock checks for single-byte ranges", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/server/vfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a89cc145832e81c32199d4ca2e1ea8bd51ed601d", "status": "affected", "version": "52fcbb92e0d3acfd1448b2a43b6595d540da5295", "versionType": "git"}, {"lessThan": "993e0158331d37c04da18efe551b5e1e35fb3078", "status": "affected", "version": "da29cd197246c85c0473259f1cad897d9d28faea", "versionType": "git"}, {"lessThan": "f751d6e39d4c937c45f8fedc66699aa7d2d52288", "status": "affected", "version": "a6f4cfa3783804336491e0edcb250c25f9b59d33", "versionType": "git"}, {"lessThan": "84c2d8e807ac489f5c91769293fb15dfdae8bae8", "status": "affected", "version": "571204e4758a528fbd67330bd4b0dfbdafb33dd8", "versionType": "git"}, {"lessThan": "07a9e289ff7edcc004f58952405f8a65c4e37512", "status": "affected", "version": "5d510ac31626ed157d2182149559430350cf2104", "versionType": "git"}, {"lessThan": "d40c24634fe077a0dc91fd11fccf44ce12b454d5", "status": "affected", "version": "5d510ac31626ed157d2182149559430350cf2104", "versionType": "git"}, {"lessThan": "6.1.188", "status": "affected", "version": "6.1.160", "versionType": "semver"}, {"lessThan": "6.6.157", "status": "affected", "version": "6.6.120", "versionType": "semver"}, {"lessThan": "6.12.110", "status": "affected", "version": "6.12.64", "versionType": "semver"}, {"lessThan": "6.18.52", "status": "affected", "version": "6.18.3", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/server/vfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.19"}, {"lessThan": "6.19", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.110", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.52", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "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\nksmbd: Do not skip lock checks for single-byte ranges\n\ncheck_lock_range() uses inclusive ranges. Its callers pass the end\noffset as start + length - 1, so start == end represents a valid\nsingle-byte range rather than an empty range.\n\nThe start == end shortcut therefore skips mandatory byte-range lock\nchecks for one-byte reads, writes, copychunk operations and one-byte\ntruncate ranges. A conflicting lock covering that byte is not checked\nand the operation is allowed to proceed.\n\nRemove the shortcut. The truncate size == inode->i_size case is already\nhandled by only calling check_lock_range() when the new size differs\nfrom the current file size."}], "id": "CVE-2026-90176", "lastModified": "2026-10-19T09:19:07.570", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-17T17:17:11.387", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/07a9e289ff7edcc004f58952405f8a65c4e37512"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/84c2d8e807ac489f5c91769293fb15dfdae8bae8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/993e0158331d37c04da18efe551b5e1e35fb3078"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a89cc145832e81c32199d4ca2e1ea8bd51ed601d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d40c24634fe077a0dc91fd11fccf44ce12b454d5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f751d6e39d4c937c45f8fedc66699aa7d2d52288"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ksmbd: Do not skip lock checks for single-byte ranges", "id": "2536251", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2536251"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-367", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nksmbd: Do not skip lock checks for single-byte ranges\ncheck_lock_range() uses inclusive ranges. Its callers pass the end\noffset as start + length - 1, so start == end represents a valid\nsingle-byte range rather than an empty range.\nThe start == end shortcut therefore skips mandatory byte-range lock\nchecks for one-byte reads, writes, copychunk operations and one-byte\ntruncate ranges. A conflicting lock covering that byte is not checked\nand the operation is allowed to proceed.\nRemove the shortcut. The truncate size == inode->i_size case is already\nhandled by only calling check_lock_range() when the new size differs\nfrom the current file size.", "A flaw was found in ksmbd, a server message block (SMB) protocol implementation within the Linux kernel. A logic error in the check_lock_range() function, which is responsible for enforcing file locks, causes it to bypass mandatory byte-range lock checks for single-byte operations. This allows an attacker to perform read, write, or truncate operations on a single byte within a file, even if that byte is protected by a conflicting lock. This could lead to unauthorized modification or access to data, potentially compromising data integrity."], "name": "CVE-2026-90176", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel-rt", "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": "Not 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": "Not affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-17T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-90176\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-90176\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90176.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[52fcbb92e0d3acfd1448b2a43b6595d540da5295,a89cc145832e81c32199d4ca2e1ea8bd51ed601d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[da29cd197246c85c0473259f1cad897d9d28faea,993e0158331d37c04da18efe551b5e1e35fb3078)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[a6f4cfa3783804336491e0edcb250c25f9b59d33,f751d6e39d4c937c45f8fedc66699aa7d2d52288)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[571204e4758a528fbd67330bd4b0dfbdafb33dd8,84c2d8e807ac489f5c91769293fb15dfdae8bae8)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5d510ac31626ed157d2182149559430350cf2104,07a9e289ff7edcc004f58952405f8a65c4e37512)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5d510ac31626ed157d2182149559430350cf2104,d40c24634fe077a0dc91fd11fccf44ce12b454d5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.1.160,6.1.188)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.6.120,6.6.157)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.12.64,6.12.110)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.18.3,6.18.52)"}}], "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": "6.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.188,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.157,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.110,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.52,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.6,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "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": "2026-09-18T17:30:11.328362+00:00", "updated": "2026-09-28T13:45:18.666779+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-362", "CWE-367"]}