CVE-2026-45259 sigqueue(2) missing capability mode restriction
A sandboxed process can bypass Capsicum restrictions to send signals to other processes, potentially causing denial of service or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-45259?
CVE-2026-45259 is a medium-severity vulnerability in Freebsd Freebsd, published on 27 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-266
Which versions are affected by CVE-2026-45259?
It affects 1 product.
Products include Freebsd Freebsd.
How do I fix CVE-2026-45259?
No fix has been published for CVE-2026-45259 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-45259 being exploited?
There is no known exploitation of CVE-2026-45259 in the wild and no public exploit code.