CVE-2026-45259: sigqueue(2) was marked as permitted in capability mode with the introduction of Capsicum in 2011, but the impl

Routine

MEDIUM 6.5MITIGATE

CVE-2026-45259 is a medium-severity flaw (CVSS 6.5) affecting freebsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-266
Published	2026-06-27
Last modified	2026-07-01

Publisher (CNA): FreeBSD · Vendor: freebsd

Last updated 2026-07-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-27 09:16 UTCPublished CVE record published
2026-07-01 14:04 UTCUpdated Record last modified

freebsd freebsd MITIGATE

Affected: 14.3 · 14.3 p1 · 14.3 p10 · 14.3 p11 · 14.3 p12 · 14.3 p13 · 14.3 p14 · 14.3 p2

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45259?

freebsd: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-45259 being exploited?

CVE-2026-45259 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45259 affect?

CVE-2026-45259 affects freebsd. Severity is medium (CVSS 6.5). 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.

How urgent is CVE-2026-45259?

Priority 23/100. No elevated risk signals yet.

Related CVEs

CVE-2026-58082 CRITICAL 9.8 MITIGATE The ISO-2022 encoding module used a stack buffer sized to MB_LEN_MAX (6 bytes) for intermediate character outp
CVE-2026-58081 CRITICAL 9.8 MITIGATE Several encoding modules, including HZ, UTF-7, VIQR, and ZW, did not properly check the size of the caller-sup
CVE-2026-58085 HIGH 7.5 MITIGATE After dispatching a decrypt operation to OCF and receiving the result, the wg(4) driver failed to check whethe
CVE-2026-58086 HIGH 8.1 MITIGATE As an inadvertent side effect of an unrelated code change, PRIV_KTRACE was always denied to a jailed root user
CVE-2026-58083 HIGH 8.4 MITIGATE While the kernel was copying knotes during fork, a knote with a timer-based filter could fire and be enqueued

References

← Back to latest CVEs