CVE-2026-90037: Linux

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux: from 3.17, before 6.12.111 (fixed in 6.12.111); from 6.13, before 6.18.51 (fixed in 6.18.51); from 6.19, before 7.2.5 (fixed in 7.2.5)

Published 2026-09-16. Last modified 2026-09-21.