Bug 2532208 (CVE-2026-89709) - CVE-2026-89709 kernel: lockd, nfsd: RCU-protect nlmsvc_ops dispatch
Summary: CVE-2026-89709 kernel: lockd, nfsd: RCU-protect nlmsvc_ops dispatch
Keywords:
Status: NEW
Alias: CVE-2026-89709
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 21:22 UTC by OSIDB Bzimport
Modified: 2026-09-21 13:56 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-09-11 21:22:15 UTC
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.


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