smb: client: fix ALIGN() overflow in symlink_data() error context loop (CVE-2026-89634) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89634

smb: client: fix ALIGN() overflow in symlink_data() error context loop

Answer in brief

CVE-2026-89634 records a Unknown severity vulnerability in smb: client: fix ALIGN() overflow in symlink_data() error context loop. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=76894f3e2f71177747b8b4763fb180e800279585 <657372ba6ea50b4474d2a6a610097eae8cd1f3e9 \|\| >=76894f3e2f71177747b8b4763fb180e800279585 <1f824f61d1df52392eaf0b74dfa5659d724fde30 \|\| >=76894f3e2f71177747b8b4763fb180e800279585 <62a3025983c8c735a3c6fc85a59316f31b59af07 \|\| >=76894f3e2f71177747b8b4763fb180e800279585 <62656b024efc21c3230eade1a847f25871c3d2bb \|\| 2d046892a493d9760c35fdaefc3017f27f91b621 \|\| >=6.0.16 <6.1	657372ba6ea50b4474d2a6a610097eae8cd1f3e9, 1f824f61d1df52392eaf0b74dfa5659d724fde30, 62a3025983c8c735a3c6fc85a59316f31b59af07, 62656b024efc21c3230eade1a847f25871c3d2bb, 6.1
Linux/Linuxgeneric	6.1	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 657372ba6ea50b4474d2a6a610097eae8cd1f3e9 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.