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. 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.
History

Mon, 29 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sat, 27 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Freebsd
Freebsd freebsd
Vendors & Products Freebsd
Freebsd freebsd

Sat, 27 Jun 2026 09:15:00 +0000

Type Values Removed Values Added
Description 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. 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.
Title sigqueue(2) missing capability mode restriction
Weaknesses CWE-266
References

cve-icon MITRE

Status: PUBLISHED

Assigner: freebsd

Published: 2026-06-27T08:59:17.853Z

Updated: 2026-06-29T13:10:40.990Z

Reserved: 2026-05-11T16:27:44.892Z

Link: CVE-2026-45259

cve-icon Vulnrichment

Updated: 2026-06-29T13:10:23.916Z

cve-icon NVD

No data.

cve-icon Redhat

No data.