CVE-2026-89659

CVE CVE-2026-89659EUVD EUVD-2026-76571Published 2026-09-11T19:45:47.000ZLast changed 2026-09-13T06:32:42.000ZCVSS 9.8

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 0; 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <4683ca76b3b7e5808338491c6eb3c20e6b4894d5; patch: 7.2.4; 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3; patch: 6.18.51; 3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56; 3.10; patch: 7.3-rc1

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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