CVE-2026-45259: sigqueue(2) missing capability mode restriction
sigqueue(2) was marked as permitted in capability mode with the introduction of Capsicum in 2011, but the implementation of kernsigqueue 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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-45259?
The severity of CVE-2026-45259 is rated as medium with a CVSS score of 6.5.
How does CVE-2026-45259 affect FreeBSD systems?
CVE-2026-45259 allows processes in capability mode to send signals to any process, potentially leading to unauthorized signal delivery.
How can I fix CVE-2026-45259?
To fix CVE-2026-45259, update to the patched version of FreeBSD that addresses the missing capability mode check in sigqueue(2).
What components are impacted by CVE-2026-45259?
CVE-2026-45259 impacts the sigqueue(2) function as part of the Capsicum framework in FreeBSD.
Is CVE-2026-45259 exploitable remotely?
CVE-2026-45259 is not remotely exploitable as it requires local access to the system.