lockd, nfsd: RCU-protect nlmsvc_ops dispatch
CVE-2026-89709 · published 11 Sept 2026
How serious is it
- Severity: high, CVSS score 8.1 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-89709?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 43943532c105ea8fe26039a1347cfda4ac0fcadc, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 6e7495972039f212e336e552b58cac9dd54611c3, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 836ce2b99bcce6d68c58edd04efbc5cd1fd581af, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 3c461a1820088fb5889d73a6522369bde45527a9
- Linux Linux: 2.6.12
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/43943532c105ea8fe26039a1347cfda4ac0fcadc
- git.kernel.org/stable/c/6e7495972039f212e336e552b58cac9dd54611c3
- git.kernel.org/stable/c/836ce2b99bcce6d68c58edd04efbc5cd1fd581af
- git.kernel.org/stable/c/3c461a1820088fb5889d73a6522369bde45527a9
- git.kernel.org/stable/c/641e5e20852359b8c31149be4598884e30652f60
Merged from CVE List. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON