{"id":"CVE-2026-89660","summary":"NFSD: Prevent client use-after-free during admin state revocation","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during admin state revocation\n\nA stateid holds only a bare pointer to its nfs4_client; a stateid\nreference does not pin it.  The client survives only because\n__destroy_client() drains its stateids before free_client() runs.\n\nnfsd4_revoke_states() drops nn-\u003eclient_lock across revoke_one_stid(),\nwhich dereferences the client to revoke a stateid and read\nclp-\u003ecl_minorversion.  A teardown racing the dropped lock can free\nthe client first.\n\nPinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and\nEXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero.\nforce_expire_client() ignores it: once its wait for cl_rpc_users to\nreach zero has passed, a later pin goes unnoticed.\n\nUnder client_lock, skip a client whose cl_time is already zero --\nforce_expire_client() clears it there before waiting -- otherwise pin\ncl_rpc_users before dropping the lock.  The walk then either sees the\nexpiry and skips, or pins in time for that wait to cover the revoke.","modified":"2026-09-13T03:47:20.148904489Z","published":"2026-09-11T19:45:48.341Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89660.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/549bd9868e9d77b07ea94870940d64342829c6ad"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bf1f948691523282cc4905bc6cd325e0c0b49e6a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e270e5a0778e5bff852c8862ce9576ce70359393"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89660.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89660"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc"},{"fixed":"549bd9868e9d77b07ea94870940d64342829c6ad"},{"fixed":"bf1f948691523282cc4905bc6cd325e0c0b49e6a"},{"fixed":"e270e5a0778e5bff852c8862ce9576ce70359393"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89660.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.9.0"},{"fixed":"6.18.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89660.json"}}],"schema_version":"1.9.0"}