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VulnerabilityPublished Updated

CVE-2026-89709: Linux kernel · lockd, nfsd: RCU-protect nlmsvc_ops dispatch

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.1 High · fixed in 43943532c105ea8fe26039a1347cfda4ac0fcadc : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 43943532c105ea8fe26039a1347cfda4ac0fcadc, 836ce2b99bcce6d68c58edd04efbc5cd1fd581af, 641e5e20852359b8c31149be4598884e30652f60 +2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 43943532c105ea8fe26039a1347cfda4ac0fcadc
Fixed in
  • 43943532c105ea8fe26039a1347cfda4ac0fcadc
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 836ce2b99bcce6d68c58edd04efbc5cd1fd581af
Fixed in
  • 836ce2b99bcce6d68c58edd04efbc5cd1fd581af
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 641e5e20852359b8c31149be4598884e30652f60
Fixed in
  • 641e5e20852359b8c31149be4598884e30652f60
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6e7495972039f212e336e552b58cac9dd54611c3
Fixed in
  • 6e7495972039f212e336e552b58cac9dd54611c3
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 3c461a1820088fb5889d73a6522369bde45527a9
Fixed in
  • 3c461a1820088fb5889d73a6522369bde45527a9
LinuxLinuxAffected
  • =2.6.12
Fixed in–

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.

References

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