CVE-2026-90037

9.8 CRITICAL

Published 2026-09-16 · Updated 2026-09-21

AI risk analysis

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.
Prioritized remediation: Update the Linux kernel to a patched version that addresses the use-after-free issue in NFSD.

kernelnfsmemory-corruptionstability

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during close_lru reaping An nfs4_openowner left on nn->close_lru after its final CLOSE keeps its last closed stateid in oo_last_closed_stid, holding only a raw pointer to its nfs4_client. The laundromat reaps timed-out entries, drops nn->client_lock, and calls nfs4_put_stid(), which dereferences the client through cl_lock. Nothing pins the client across that window, so a concurrent force_expire_client() can free it and nfs4_put_stid() reads freed memory. __destroy_client() hits the same race, walking clp->cl_openowners without cl_lock. Pin the client with cl_rpc_users before dropping client_lock, and skip clients already expiring. __destroy_client() then cleans up its own close_lru entries through release_last_closed_stateid(), so teardown no longer races the laundromat.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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