Expired Pointer Dereference Affecting libperf package, versions *


Severity

Recommended
0.0
high
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.44% (37th percentile)

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  • Snyk IDSNYK-CENTOS10-LIBPERF-19843422
  • published16 Sept 2026
  • disclosed11 Sept 2026

Introduced: 11 Sep 2026

NewCVE-2026-89659  (opens in a new tab)
CWE-825  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 libperf.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libperf package and not the libperf package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

NFSD: Prevent client use-after-free during delegation revoke

A delegation stateid holds only a bare pointer to its owning nfs4_client and does not keep it alive. The client survives its stateids only because __destroy_client() drains cl_delegations and cl_revoked before free_client() runs.

nfs4_laundromat() breaks that invariant: it unhashes an expired delegation from cl_delegations, drops deleg_lock, then revoke_delegation() relinks it onto cl_revoked under cl_lock. In that window the delegation is on neither list, so client_has_state() can report no remaining state.

Every teardown path first requires cl_rpc_users to be zero, but the laundromat holds no such reference. A client whose recalled delegation has just timed out can therefore reach free_client() while revoke_delegation() is still about to dereference cl_lock, a use-after-free.

Pin the client with cl_rpc_users across the revoke so teardown blocks until it completes, then reap the delegation from cl_revoked. A client already expiring reaps its own, so skip it and leave the delegation on del_recall_lru.

CVSS Base Scores

version 3.1