{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89703","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.750Z","datePublished":"2026-09-11T19:46:20.280Z","dateUpdated":"2026-09-13T06:33:24.763Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-13T06:33:24.763Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations\n\nnfsd4_drop_revoked_stid() handles FREE_STATEID for admin-revoked\ndelegations but does not set SC_STATUS_FREED before releasing cl_lock.\nrevoke_delegation() uses this flag to detect whether FREE_STATEID has\nalready processed the delegation -- without it, the freed delegation is\nadded to cl_revoked via list_add(), producing a use-after-free when\ncl_revoked is later traversed in __destroy_client().\n\nThe SC_STATUS_REVOKED path in nfsd4_free_stateid() (line 7983) already\nsets SC_STATUS_FREED correctly. Apply the same pattern to the\nSC_STATUS_ADMIN_REVOKED path in nfsd4_drop_revoked_stid()."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The UAF is in nfsd nfsd4_drop_revoked_stid()/revoke_delegation() in fs/nfsd/nfs4state.c. A remote NFSv4 peer reaches it over TCP/2049 via svc_process to nfsd_dispatch to nfsd4_proc_compound: SEQUENCE then FREE_STATEID (ALLOWED_WITHOUT_FH), or a v4.0 op that hits nfsd40_drop_revoked_stid on an admin-revoked delegation.\nAC:L - The attacker holds a delegation and retries FREE_STATEID (or v4.0 use of that stateid) while nfsd4_revoke_states() unhashes with ADMIN_REVOKED and revoke_delegation() runs, then DESTROY_CLIENTID/expire so __destroy_client() walks cl_revoked. They control the NFS side of the race; unexport is a routine nfsd operational condition, not an uninfluenced layout.\nPR:N - Typical nfsd deployments use AUTH_SYS/AUTH_NULL with no cryptographic RPC authentication. Any host allowed by the export can EXCHANGE_ID/CREATE_SESSION or SETCLIENTID, OPEN to receive a delegation, and issue FREE_STATEID; no local Linux account or capability on the NFS server is required.\nUI:N - The attacker sends the NFSv4 compounds that obtain the delegation, FREE_STATEID, and client teardown. Administrative unlock_filesystem/unexport is a server operational condition (exportfs -u or volume detach), not a required victim user action such as mounting or opening a file.\nS:U - The use-after-free corrupts a kmalloc'd nfs4_delegation (deleg_slab) in the NFS server kernel. Impact stays in that host kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Without SC_STATUS_FREED, revoke_delegation() list_add()s a kmem_cache_free'd nfs4_delegation onto cl_revoked (KMEM_CACHE flags 0, not SLAB_TYPESAFE_BY_RCU). __destroy_client() then walks that freed object; slab reuse yields an arbitrary kernel-read primitive. Per guidance a UAF is C:H.\nI:H - list_add on the freed dl_recall_lru and later list_del_init/nfs4_put_stid in __destroy_client() write through reclaimed deleg_slab, including sc_free. That is a heap-spray write and control-flow hijack primitive. Per guidance a UAF is I:H.\nA:H - Use-after-free of nfs4_delegation when __destroy_client() traverses cl_revoked oopses or panics the nfsd thread even without full exploitation, fully denying service of the NFS server host."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"],"versions":[{"version":"8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a","lessThan":"d832a0587528853d45481d1faf75d4b5d062adaf","status":"affected","versionType":"git"},{"version":"8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a","lessThan":"1e4795766719ffd74b8cf0f2fde4a1350f8326bf","status":"affected","versionType":"git"},{"version":"8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a","lessThan":"a6d89032e5c6620d5bb44582a72555ce07bf1c2e","status":"affected","versionType":"git"},{"version":"8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a","lessThan":"650d370cfbc66a96dd14d517bd704689b5bda4e5","status":"affected","versionType":"git"},{"version":"967faa26f313a62e7bebc55d5b8122eaee43b929","status":"affected","versionType":"git"},{"version":"6.11.6","lessThan":"6.12","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/nfsd/nfs4state.c"],"versions":[{"version":"6.12","status":"affected"},{"version":"0","lessThan":"6.12","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.3-rc1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11.6"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/d832a0587528853d45481d1faf75d4b5d062adaf"},{"url":"https://git.kernel.org/stable/c/1e4795766719ffd74b8cf0f2fde4a1350f8326bf"},{"url":"https://git.kernel.org/stable/c/a6d89032e5c6620d5bb44582a72555ce07bf1c2e"},{"url":"https://git.kernel.org/stable/c/650d370cfbc66a96dd14d517bd704689b5bda4e5"}],"title":"nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations","x_generator":{"engine":"bippy-1.2.0"}}}}