# CVE-2026-45259 — FreeBSD

> As of 2026-06-27, CVE-2026-45259 is a vulnerability in FreeBSD, EPSS 0.1% (3.7th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-45259 as of 2026-06-27; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-06-27

## 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.

The record classifies CVE-2026-45259 under weakness class [CWE-266](https://intel.threadlinqs.com/cwe/CWE-266). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 100 days ago.

## Severity and exploitation probability

- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 3.7% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 0.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-27

## Is CVE-2026-45259 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [FreeBSD](https://intel.threadlinqs.com/vendors/freebsd): FreeBSD

## How to fix CVE-2026-45259

No vendor patch reference has been recorded for CVE-2026-45259 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-45259

No threat campaign in the Threadlinqs corpus currently references CVE-2026-45259, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-06-29. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [security.freebsd.org — vendor advisory](https://security.freebsd.org/advisories/FreeBSD-SA-26:28.capsicum.asc)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-45259
Full detection coverage and IOCs for threats exploiting CVE-2026-45259 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp