CVE-2026-89709

lockd, nfsd: RCU-protect nlmsvc_ops dispatch

HIGH
8.1
CVSS Score
Published: September 11, 2026 at 07:46 PM UTC
Updated: October 21, 2026 at 01:20 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH8.1
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: lockd, nfsd: RCU-protect nlmsvc_ops dispatch nlmsvc_ops is published by nfsd_lockd_init() and cleared by nfsd_lockd_shutdown() with plain stores, while lockd dereferences it unguarded from dispatch sites in fs/lockd/svcsubs.c. The pointer targets nfsd's .rodata and the fopen/fclose callbacks live in nfsd's .text, so a stale load after rmmod nfsd results in either a NULL deref or a module-text use-after-free. Declare nlmsvc_ops as __rcu, publish via rcu_assign_pointer(), clear via RCU_INIT_POINTER() + synchronize_rcu(). Add a struct module *owner field to nlmsvc_binding and pin the module across indirect calls with try_module_get/module_put. When the binding is torn down, fall back to fput() to avoid leaking struct file references.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 3c461a1820088fb5889d73a6522369bde45527a9 (fixed)
Vendor states this is fixed in 641e5e20852359b8c31149be4598884e30652f60 (fixed)
Vendor states this is fixed in 2.6.12 (unaffected)
Vendor states this is fixed in 6.12.114 (unaffected)
Vendor states this is fixed in 6.18.57 (unaffected)
Vendor states this is fixed in 6.6.160 (unaffected)
Vendor states this is fixed in 7.2.4 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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