CVE-2026-89691: Linux

High severity, CVSS 7.1. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: nfsd: clear opcnt on compound arg release to prevent OOB read nfsd4_release_compoundargs() resets args->ops to the inline iops[8] array when the dynamically-allocated ops buffer is freed, but leaves args->opcnt at its original value (which can be up to 200 for NFSv4.1+ compounds). If rq_status_counter is stuck at an odd value (which can happen when nfsd_dispatch() hits an error path after setting it odd), the RPC status dumpit handler reads min(opcnt, 16) entries from args->ops[]. Since iops only has 8 elements and is the last field in struct nfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory and leaks it to userspace via netlink. Zero opcnt unconditionally in nfsd4_release_compoundargs() so stale compound metadata is never exposed through the status interface. [ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]

Affected products

• Linux Linux: from 6.7, before 6.12.109 (fixed in 6.12.109); from 6.13, before 6.18.50 (fixed in 6.18.50); from 6.19, before 7.2.4 (fixed in 7.2.4)

Published 2026-09-11. Last modified 2026-09-13.