CVE-2026-89660 Affecting kernel-azure-extra package, versions <6.12.0-160000.39.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.62% (48th percentile)

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  • Snyk IDSNYK-SLES1600-KERNELAZUREEXTRA-21354229
  • published21 Oct 2026
  • disclosed12 Oct 2026

Introduced: 12 Oct 2026

NewCVE-2026-89660  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-azure-extra to version 6.12.0-160000.39.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-azure-extra package and not the kernel-azure-extra package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

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

NFSD: Prevent client use-after-free during admin state revocation

A stateid holds only a bare pointer to its nfs4_client; a stateid reference does not pin it. The client survives only because __destroy_client() drains its stateids before free_client() runs.

nfsd4_revoke_states() drops nn->client_lock across revoke_one_stid(), which dereferences the client to revoke a stateid and read clp->cl_minorversion. A teardown racing the dropped lock can free the client first.

Pinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and EXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero. force_expire_client() ignores it: once its wait for cl_rpc_users to reach zero has passed, a later pin goes unnoticed.

Under client_lock, skip a client whose cl_time is already zero -- force_expire_client() clears it there before waiting -- otherwise pin cl_rpc_users before dropping the lock. The walk then either sees the expiry and skips, or pins in time for that wait to cover the revoke.

CVSS Base Scores

version 3.1