NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup (CVE-2026-89658) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89658

NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup

Answer in brief

CVE-2026-89658 records a Unknown severity vulnerability in NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup. 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	>=d688d8585e6bea5e4e37f7497feea93b6b0a469c <0ae0d2b5c5a1b39c0b3c15d96b32a5b0c583d519 \|\| >=d688d8585e6bea5e4e37f7497feea93b6b0a469c <b413ec5b23e3445dc9c4f273116078e2d4747626 \|\| >=d688d8585e6bea5e4e37f7497feea93b6b0a469c <81cf7f1413862f87b078920c838460a6a88aa030 \|\| >=d688d8585e6bea5e4e37f7497feea93b6b0a469c <7b4f8a1586c42d3afc3c0ac779af2db7ab1a5c55	0ae0d2b5c5a1b39c0b3c15d96b32a5b0c583d519, b413ec5b23e3445dc9c4f273116078e2d4747626, 81cf7f1413862f87b078920c838460a6a88aa030, 7b4f8a1586c42d3afc3c0ac779af2db7ab1a5c55
Linux/Linuxgeneric	6.9	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 0ae0d2b5c5a1b39c0b3c15d96b32a5b0c583d519 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: NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup nfs40_clean_admin_revoked() takes a stateid reference under clp->cl_lock, drops nn->client_lock, and calls nfsd4_drop_revoked_stid(), which dereferences the stateid's client through s->sc_client->cl_lock. The stateid reference does not pin the client, so a teardown racing the dropped lock can free the client while nfsd4_drop_revoked_stid() is still using it. This cleanup runs from the laundromat, so a periodic sweep can race force_expire_client() driven by a write to the clients/<id>/ctl file. Skip a client that is already expiring and otherwise pin it with cl_rpc_users under client_lock before dropping the lock, matching nfsd4_revoke_states().

Quoted source text, attributed separately from HOL analysis.