CVE-2026-45259

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.

CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0009

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-266 CWE-266

Affected Products

Vendor	Product	Versions
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All
freebsd	freebsd	All

References

Advisories & Patches

https://security.freebsd.org/advisories/FreeBSD-SA-26:28.capsicum.asc

Frequently Asked Questions

What is CVE-2026-45259? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-45259? +

CVE-2026-45259 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0009, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-45259? +

CVE-2026-45259 affects products from freebsd, specifically: freebsd. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-45259? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-56513

Karmada is a Kubernetes management system that allows users to run cloud-native applications across multiple Kubernetes clusters and clouds. Prior …

CVE-2025-26523

This vulnerability exists in RupeeWeb trading platform due to insufficient authorization controls on certain API endpoints handling addition and deletion …

CVE-2025-0131

An incorrect privilege management vulnerability in the OPSWAT MetaDefender Endpoint Security SDK used by the Palo Alto Networks GlobalProtect™ app …

CVE-2025-48741

A Broken Access Control vulnerability in StrangeBee TheHive 5.2.0 before 5.2.16, 5.3.0 before 5.3.11, and 5.4.0 before 5.4.10 allows remote, …

CVE-2025-4228

An incorrect privilege assignment vulnerability in Palo Alto Networks Cortex® XDR Broker VM allows an authenticated administrative user to execute …

CVE-2025-0139

An incorrect privilege assignment vulnerability in Palo Alto Networks Autonomous Digital Experience Manager allows a locally authenticated low privileged user …