cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC (CVE-2026-89639) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89639

cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC

Answer in brief

CVE-2026-89639 records a Unknown severity vulnerability in cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC. 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	>=efbcecdecefc26fa062c0e8210533ccad7d6bd4a <8b9b10fe5b8b492b27b9f4546742ea541a650213 \|\| >=fa724e235cfdb0fb0bb427d0f9dfe864ae27403e <81fc3868a7f726980ff845c1d0d271051e5f0f45 \|\| >=fa724e235cfdb0fb0bb427d0f9dfe864ae27403e <364b183230586a62660a7280c1eb20138338eeb5 \|\| 6838bcac954487cc0a3c8a4ee1b3a3a30e244dc9 \|\| 75640976cf474eb41682a13f2dbe9534ac26ca50 \|\| 3513f3931c579ba2a715784c6dedc59e0d9282ee \|\| >=6.18.44 <6.18.50 \|\| >=6.12.105 <6.13 \|\| >=7.1.8 <7.2	8b9b10fe5b8b492b27b9f4546742ea541a650213, 81fc3868a7f726980ff845c1d0d271051e5f0f45, 364b183230586a62660a7280c1eb20138338eeb5, 6.18.50, 6.13, 7.2
Linux/Linuxgeneric	7.2	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 8b9b10fe5b8b492b27b9f4546742ea541a650213 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: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC cifs_do_truncate() is invoked from cifs_open() without i_rwsem, so it cannot use cifs_resize_file_locked() to perform a proper fscache cookie resize. Instead, add cifs_invalidate_cache() after cifs_setsize(). cifs_invalidate_cache() calls fscache_invalidate(), which works without holding i_rwsem: it unconditionally increments inval_counter and sets FSCACHE_COOKIE_NO_DATA_TO_READ, ensuring that stale cached data is not served once the cookie is later activated by fscache_use_cookie(). Truncation to zero leaves no valid cached data, making invalidation the correct semantic here.

Quoted source text, attributed separately from HOL analysis.