CVE-2026-89639

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89639", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.740Z", "datePublished": "2026-09-11T19:45:32.532Z", "dateUpdated": "2026-10-19T08:50:11.190Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:50:11.190Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC\n\ncifs_do_truncate() is invoked from cifs_open() without i_rwsem, so it\ncannot use cifs_resize_file_locked() to perform a proper fscache cookie\nresize. Instead, add cifs_invalidate_cache() after cifs_setsize().\n\ncifs_invalidate_cache() calls fscache_invalidate(), which works without\nholding i_rwsem: it unconditionally increments inval_counter and sets\nFSCACHE_COOKIE_NO_DATA_TO_READ, ensuring that stale cached data is not\nserved once the cookie is later activated by fscache_use_cookie().\nTruncation to zero leaves no valid cached data, making invalidation the\ncorrect semantic here."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - cifs_do_truncate() runs from cifs_open() on the SMB client during a local open/openat with O_TRUNC on a mounted CIFS share (fs/smb/client/), not from ksmbd/nfsd or demux-thread packet parsing; a remote SMB peer cannot invoke this path.\nAC:L - A write-capable open with O_TRUNC deterministically skips fscache invalidation, then the same cifs_open() activates the cookie via fscache_use_cookie(); the attacker can also hold another fd so the cookie is already active, with no race or layout outside their control.\nPR:L - O_TRUNC requires only MAY_WRITE on the target inode, which an ordinary local user has on an already-mounted CIFS share; no init-namespace root, CAP_SYS_ADMIN, or user-namespace mount of CIFS is needed.\nUI:N - The attacker issues open(O_TRUNC) and follow-on reads/writes themselves; on common fstab/autofs/CIFS-home deployments with the fsc option already set, no other user must mount the share or open the file.\nS:U - Stale data stays within the local CIFS client's fscache and the same SMB file's contents; this is not a VM escape, IOMMU bypass, or other cross-authority boundary crossing.\nC:H - After O_TRUNC the cookie is activated without FSCACHE_COOKIE_NO_DATA_TO_READ, so later reads (including holes after a size-extending write) can return the full previously truncated file contents that should have been discarded.\nI:H - The same stale cookie presents discarded bytes as current file data and can persist them to the SMB server via netfs read-modify-write/writeback, fully replacing zeros or newly written contents on that file.\nA:N - The flaw is fscache coherency only; it does not oops, panic, deadlock, or exhaust kernel resources, so host availability is unaffected."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/file.c"], "versions": [{"version": "efbcecdecefc26fa062c0e8210533ccad7d6bd4a", "lessThan": "8b9b10fe5b8b492b27b9f4546742ea541a650213", "status": "affected", "versionType": "git"}, {"version": "fa724e235cfdb0fb0bb427d0f9dfe864ae27403e", "lessThan": "81fc3868a7f726980ff845c1d0d271051e5f0f45", "status": "affected", "versionType": "git"}, {"version": "fa724e235cfdb0fb0bb427d0f9dfe864ae27403e", "lessThan": "364b183230586a62660a7280c1eb20138338eeb5", "status": "affected", "versionType": "git"}, {"version": "6838bcac954487cc0a3c8a4ee1b3a3a30e244dc9", "status": "affected", "versionType": "git"}, {"version": "75640976cf474eb41682a13f2dbe9534ac26ca50", "status": "affected", "versionType": "git"}, {"version": "3513f3931c579ba2a715784c6dedc59e0d9282ee", "status": "affected", "versionType": "git"}, {"version": "6.18.44", "lessThan": "6.18.50", "status": "affected", "versionType": "semver"}, {"version": "6.12.105", "lessThan": "6.13", "status": "affected", "versionType": "semver"}, {"version": "7.1.8", "lessThan": "7.2", "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/client/file.c"], "versions": [{"version": "7.2", "status": "affected"}, {"version": "0", "lessThan": "7.2", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "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": "6.18.44", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.105"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1.8"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/8b9b10fe5b8b492b27b9f4546742ea541a650213"}, {"url": "https://git.kernel.org/stable/c/81fc3868a7f726980ff845c1d0d271051e5f0f45"}, {"url": "https://git.kernel.org/stable/c/364b183230586a62660a7280c1eb20138338eeb5"}], "title": "cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/client/file.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "8b9b10fe5b8b492b27b9f4546742ea541a650213", "status": "affected", "version": "efbcecdecefc26fa062c0e8210533ccad7d6bd4a", "versionType": "git"}, {"lessThan": "81fc3868a7f726980ff845c1d0d271051e5f0f45", "status": "affected", "version": "fa724e235cfdb0fb0bb427d0f9dfe864ae27403e", "versionType": "git"}, {"lessThan": "364b183230586a62660a7280c1eb20138338eeb5", "status": "affected", "version": "fa724e235cfdb0fb0bb427d0f9dfe864ae27403e", "versionType": "git"}, {"status": "affected", "version": "6838bcac954487cc0a3c8a4ee1b3a3a30e244dc9", "versionType": "git"}, {"status": "affected", "version": "75640976cf474eb41682a13f2dbe9534ac26ca50", "versionType": "git"}, {"status": "affected", "version": "3513f3931c579ba2a715784c6dedc59e0d9282ee", "versionType": "git"}, {"lessThan": "6.18.50", "status": "affected", "version": "6.18.44", "versionType": "semver"}, {"lessThan": "6.13", "status": "affected", "version": "6.12.105", "versionType": "semver"}, {"lessThan": "7.2", "status": "affected", "version": "7.1.8", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/client/file.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.2"}, {"lessThan": "7.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "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\ncifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC\n\ncifs_do_truncate() is invoked from cifs_open() without i_rwsem, so it\ncannot use cifs_resize_file_locked() to perform a proper fscache cookie\nresize. Instead, add cifs_invalidate_cache() after cifs_setsize().\n\ncifs_invalidate_cache() calls fscache_invalidate(), which works without\nholding i_rwsem: it unconditionally increments inval_counter and sets\nFSCACHE_COOKIE_NO_DATA_TO_READ, ensuring that stale cached data is not\nserved once the cookie is later activated by fscache_use_cookie().\nTruncation to zero leaves no valid cached data, making invalidation the\ncorrect semantic here."}], "id": "CVE-2026-89639", "lastModified": "2026-10-19T09:18:01.053", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.2, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:19:49.617", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/364b183230586a62660a7280c1eb20138338eeb5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/81fc3868a7f726980ff845c1d0d271051e5f0f45"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8b9b10fe5b8b492b27b9f4546742ea541a650213"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel CIFS: Information disclosure due to improper cache invalidation during file truncation", "id": "2532382", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532382"}, "csaw": false, "cvss3": {"cvss3_base_score": "3.3", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "status": "draft"}, "cwe": "CWE-524", "details": ["A flaw was found in the Linux kernel's Common Internet File System (CIFS) implementation. When a file is truncated, the `cifs_do_truncate()` function does not properly invalidate the file system cache (fscache). This oversight can lead to stale cached data being served to users, potentially resulting in information disclosure or data inconsistency."], "name": "CVE-2026-89639", "public_date": "2026-09-11T19:45:32Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89639\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89639\nhttps://git.kernel.org/stable/c/364b183230586a62660a7280c1eb20138338eeb5\nhttps://git.kernel.org/stable/c/81fc3868a7f726980ff845c1d0d271051e5f0f45\nhttps://git.kernel.org/stable/c/8b9b10fe5b8b492b27b9f4546742ea541a650213"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[efbcecdecefc26fa062c0e8210533ccad7d6bd4a,8b9b10fe5b8b492b27b9f4546742ea541a650213)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[fa724e235cfdb0fb0bb427d0f9dfe864ae27403e,81fc3868a7f726980ff845c1d0d271051e5f0f45)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[fa724e235cfdb0fb0bb427d0f9dfe864ae27403e,364b183230586a62660a7280c1eb20138338eeb5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "6838bcac954487cc0a3c8a4ee1b3a3a30e244dc9"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "75640976cf474eb41682a13f2dbe9534ac26ca50"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "3513f3931c579ba2a715784c6dedc59e0d9282ee"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.18.44,6.18.50)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[6.12.105,6.13)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[7.1.8,7.2)"}}], "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": "7.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.50,6.19.0]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.4,7.3.0]"}}, {"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": "2026-09-12T09:15:12.757211+00:00", "updated": "2026-09-15T21:15:14.617662+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}