{"api_version":"1","generated_at":"2026-10-27T04:32:00+00:00","cve":"CVE-2026-89634","urls":{"html":"https://cve.report/CVE-2026-89634","api":"https://cve.report/api/cve/CVE-2026-89634.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89634","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89634"},"summary":{"title":"smb: client: fix ALIGN() overflow in symlink_data() error context loop","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix ALIGN() overflow in symlink_data() error context loop\n\nThe check added by commit 7d9a7f1f96cd (\"smb/client: fix possible\ninfinite loop and oob read in symlink_data()\") compared the post-ALIGN\nlength against the remaining buffer, but ALIGN() itself can overflow:\nfor ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9), ALIGN(x, 8)\nwraps to 0, so the subsequent bounds check passes, and the loop\nadvances by zero bytes leaving 'p' pointing into stale data.\n\nFix by checking the raw ErrorDataLength against the remaining space\nbefore applying ALIGN(), then checking again after.  Since raw_len is\nbounded by the buffer, raw_len + 7 cannot overflow, so the second check\nis an exact post-alignment bounds guard.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:49","updated_at":"2026-10-19 09:18:00"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30","name":"https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0","name":"https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf","name":"https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9","name":"https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb","name":"https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07","name":"https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89634","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89634","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 2b4a25baa0b936fef6915c0459925077b324ecaf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 b89d678f9eafcf8d74885983166ba26b40a04ea0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 657372ba6ea50b4474d2a6a610097eae8cd1f3e9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 1f824f61d1df52392eaf0b74dfa5659d724fde30 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 62a3025983c8c735a3c6fc85a59316f31b59af07 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 76894f3e2f71177747b8b4763fb180e800279585 62656b024efc21c3230eade1a847f25871c3d2bb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2d046892a493d9760c35fdaefc3017f27f91b621 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.0.16 6.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.188 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"89634","cve":"CVE-2026-89634","epss":"0.006530000","percentile":"0.493550000","score_date":"2026-09-14","updated_at":"2026-09-15 00:00:41"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/smb/client/smb2file.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2b4a25baa0b936fef6915c0459925077b324ecaf","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"lessThan":"b89d678f9eafcf8d74885983166ba26b40a04ea0","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"lessThan":"657372ba6ea50b4474d2a6a610097eae8cd1f3e9","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"lessThan":"1f824f61d1df52392eaf0b74dfa5659d724fde30","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"lessThan":"62a3025983c8c735a3c6fc85a59316f31b59af07","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"lessThan":"62656b024efc21c3230eade1a847f25871c3d2bb","status":"affected","version":"76894f3e2f71177747b8b4763fb180e800279585","versionType":"git"},{"status":"affected","version":"2d046892a493d9760c35fdaefc3017f27f91b621","versionType":"git"},{"lessThan":"6.1","status":"affected","version":"6.0.16","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/client/smb2file.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.1"},{"lessThan":"6.1","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":"6.12.109","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"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"6.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix ALIGN() overflow in symlink_data() error context loop\n\nThe check added by commit 7d9a7f1f96cd (\"smb/client: fix possible\ninfinite loop and oob read in symlink_data()\") compared the post-ALIGN\nlength against the remaining buffer, but ALIGN() itself can overflow:\nfor ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9), ALIGN(x, 8)\nwraps to 0, so the subsequent bounds check passes, and the loop\nadvances by zero bytes leaving 'p' pointing into stale data.\n\nFix by checking the raw ErrorDataLength against the remaining space\nbefore applying ALIGN(), then checking again after.  Since raw_len is\nbounded by the buffer, raw_len + 7 cannot overflow, so the second check\nis an exact post-alignment bounds guard."}],"metrics":[{"cvssV3_1":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The flaw is in the SMB client parser of a STATUS_STOPPED_ON_SYMLINK CREATE error returned over TCP/445; a malicious, compromised, or MITM SMB server supplies the crafted ErrorDataLength in the network response.\nAC:L - The attacker fully controls ErrorContextCount, ErrorId, and ErrorDataLength in a single SMB2 error response; setting ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9) makes ALIGN() wrap to 0 and bypasses the bounds check with no race or attacker-uncontrolled condition.\nPR:N - The attacker is the remote SMB peer and needs no account or capability on the victim client; guest/null sessions and already-established mounts are enough for the client to parse the malformed error.\nUI:N - Persistent fstab, autofs, and systemd automounts plus reconnect-driven path walks already open/lookup files on the share, so a compromised or MITM'd server can return the crafted symlink error during ordinary client activity with no extra user action.\nS:U - Impact stays in the client kernel SMB parser and its memory; this is not a VM escape, IOMMU bypass, or cross-scope sandbox escape.\nC:H - The ALIGN overflow bypasses the ErrorDataLength bounds check added to stop out-of-bounds reads in this loop (CVE-2026-52967/CVE-2026-31613); a stale overlapping context pointer can then be parsed as symlink PathBuffer data and UTF-16-decoded into a userspace target.\nI:N - The defect only mis-advances a read-side parser pointer after ALIGN() wraps to 0; it does not write out of bounds or provide a kernel memory-modification primitive.\nA:H - With the skip length wrapped to 0 the error-context loop fails to consume the declared payload and can stall or walk a stale pointer; that is the remaining hole in the 32-bit infinite-loop/OOB class in this function and can hang or oops the client kernel."}]}],"providerMetadata":{"dateUpdated":"2026-10-19T08:50:06.331Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf"},{"url":"https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0"},{"url":"https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9"},{"url":"https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30"},{"url":"https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07"},{"url":"https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb"}],"title":"smb: client: fix ALIGN() overflow in symlink_data() error context loop","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89634","datePublished":"2026-09-11T19:45:28.823Z","dateReserved":"2026-09-11T19:38:34.739Z","dateUpdated":"2026-10-19T08:50:06.331Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:49","lastModifiedDate":"2026-10-19 09:18:00","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89634","Ordinal":"1","Title":"smb: client: fix ALIGN() overflow in symlink_data() error contex","CVE":"CVE-2026-89634","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89634","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix ALIGN() overflow in symlink_data() error context loop\n\nThe check added by commit 7d9a7f1f96cd (\"smb/client: fix possible\ninfinite loop and oob read in symlink_data()\") compared the post-ALIGN\nlength against the remaining buffer, but ALIGN() itself can overflow:\nfor ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9), ALIGN(x, 8)\nwraps to 0, so the subsequent bounds check passes, and the loop\nadvances by zero bytes leaving 'p' pointing into stale data.\n\nFix by checking the raw ErrorDataLength against the remaining space\nbefore applying ALIGN(), then checking again after.  Since raw_len is\nbounded by the buffer, raw_len + 7 cannot overflow, so the second check\nis an exact post-alignment bounds guard.","Type":"Description","Title":"smb: client: fix ALIGN() overflow in symlink_data() error contex"}]}}}