CVE-2026-89634smb: client: fix ALIGN() overflow in symlink_data() error context loop
- 9.1CriticalCVSS base score
- 0.69%Exploitation in 30 daysEPSS · top 47% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix ALIGN() overflow in symlink_data() error context loop The check added by commit 7d9a7f1f96cd ("smb/client: fix possible infinite loop and oob read in symlink_data()") compared the post-ALIGN length against the remaining buffer, but ALIGN() itself can overflow: for ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9), ALIGN(x, 8) wraps to 0, so the subsequent bounds check passes, and the loop advances by zero bytes leaving 'p' pointing into stale data. Fix by checking the raw ErrorDataLength against the remaining space before applying ALIGN(), then checking again after. Since raw_len is bounded by the buffer, raw_len + 7 cannot overflow, so the second check is an exact post-alignment bounds guard.
Timeline
ID reserved
By Linux
Published
- 38 days later
· 38 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| NVDNVD · Received | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.69% · top 47% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.
Affected products
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < 2b4a25baa0b936fef6915c0459925077b324ecaf
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < b89d678f9eafcf8d74885983166ba26b40a04ea0
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < 657372ba6ea50b4474d2a6a610097eae8cd1f3e9
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < 1f824f61d1df52392eaf0b74dfa5659d724fde30
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < 62a3025983c8c735a3c6fc85a59316f31b59af07
- affected 76894f3e2f71177747b8b4763fb180e800279585 – < 62656b024efc21c3230eade1a847f25871c3d2bb
- affected 2d046892a493d9760c35fdaefc3017f27f91b621
- affected 6.0.16 – < 6.1
- affected 6.1
- unaffected < 6.1
- unaffected 6.1.188 – ≤ 6.1.*
- unaffected 6.6.157 – ≤ 6.6.*
- unaffected 6.12.109 – ≤ 6.12.*
- unaffected 6.18.50 – ≤ 6.18.*
- unaffected 7.2.4 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References6
- https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf (opens in a new tab)
- https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0 (opens in a new tab)
- https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9 (opens in a new tab)
- https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30 (opens in a new tab)
- https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07 (opens in a new tab)
- https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-76546 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-89634)Record last updated .