{"id":"CVE-2026-90037","published":"2026-09-16T11:17:16.910","lastModified":"2026-09-21T14:17:27.983","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Prevent client use-after-free during close_lru reaping\n\nAn nfs4_openowner left on nn->close_lru after its final CLOSE keeps\nits last closed stateid in oo_last_closed_stid, holding only a raw\npointer to its nfs4_client. The laundromat reaps timed-out entries,\ndrops nn->client_lock, and calls nfs4_put_stid(), which dereferences\nthe client through cl_lock. Nothing pins the client across that\nwindow, so a concurrent force_expire_client() can free it and\nnfs4_put_stid() reads freed memory. __destroy_client() hits the same\nrace, walking clp->cl_openowners without cl_lock.\n\nPin the client with cl_rpc_users before dropping client_lock, and\nskip clients already expiring. __destroy_client() then cleans up its\nown close_lru entries through release_last_closed_stateid(), so\nteardown no longer races the laundromat.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0763482227822f7343557f086afc382086d56c4c","tags":[]},{"url":"https://git.kernel.org/stable/c/2330b788d732f43668b965b3105b37ceb276dfea","tags":[]},{"url":"https://git.kernel.org/stable/c/83dd59ac1c3455c2c7d8ddb582d980a13199b9b3","tags":[]},{"url":"https://git.kernel.org/stable/c/e57a9ed34ea8c17e831de59b8f1a6b2d80d347a1","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This vulnerability allows an attacker to exploit a use-after-free condition in the Linux kernel's NFS daemon (NFSD), potentially leading to memory corruption and system instability.","exploitability":"Exploitation requires concurrent access to the NFS client and server, making it moderately difficult. Precondition is that the client must have left an openowner on the close_lru after its final CLOSE operation.","blast_radius":"If exploited, this could lead to severe system instability or even remote code execution in extreme cases, depending on how the kernel handles memory corruption.","remediation":"Update the Linux kernel to a patched version that addresses the use-after-free issue in NFSD.","tags":["kernel","nfs","memory-corruption","stability"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-23T08:45:19.627Z"}}