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Fixed

sigqueue(2) missing capability mode restriction

FreeBSD-SA-26:28.capsicum · CVE-2026-45259

Our decision for FreeSense

FreeBSD corrected this on 2026-05-29, before the FreeBSD source pin of every FreeSense version.

  • Advisory: corrected 2026-05-29
  • FreeSense 1.0 pin: e004ff15f87e (2026-08-03)
  • FreeSense 1.1 pin: a52c50b4b7c2 (2026-10-04)
  • FreeSense 1.2 pin: a52c50b4b7c2 (2026-10-04)
Decided by rules, not yet reviewed. The status comes from the advisory's correction date and the build configuration. A maintainer has not looked at whether FreeSense is exposed in practice. How we triage

By FreeSense version

VersionStatusFreeBSD pin
FreeSense 1.01.0.7 · frozen, no further fixesFixedFreeBSD pin of 2026-08-032026-08-03e004ff15
FreeSense 1.11.1.9FixedFreeBSD pin of 2026-10-042026-10-04a52c50b4
FreeSense 1.21.2.0-DEVELOPMENTFixedFreeBSD pin of 2026-10-042026-10-04a52c50b4

Workaround

No workaround is available.

What FreeBSD says

sigqueue(2) was marked as permitted in capability mode with the introduction of Capsicum in 2011, but the implementation of kern_sigqueue did not include a capability mode check restricting signal delivery to the calling process's own PID.

Impact

A process in capability mode can use sigqueue(2) to send signals to any process it could signal following standard Unix permissions, bypassing the Capsicum sandbox restriction. A compromised sandboxed process could interfere with other processes, for example by sending SIGKILL or SIGSTOP. This could be any process running as the same user, or any process, for a superuser sandboxed process.

Excerpt from the FreeBSD advisory. Read the original for the full text and the fix.

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