CVE-2026-45259

Cross-process interruption via unrestricted sigqueue delivery

Published Jun 27, 2026 · Updated Jun 27, 2026

Privilege-boundary bypass in Capsicum on affected FreeBSD releases allows local users to interrupt other permitted processes via sigqueue(2). The kern_sigqueue implementation omits the capability-mode check that limits signal delivery to the caller's own PID, so sandboxed code can target any PID allowed by ordinary Unix permissions. Exploitation requires code inside a Capsicum sandbox; same-user targets can be stopped or killed, while a sandboxed superuser process can signal any process.

CVSS severity6.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege-boundary bypass in Capsicum on affected FreeBSD releases allows local users to interrupt other permitted processes via sigqueue(2). The kern_sigqueue implementation omits the capability-mode check that limits signal delivery to the caller's own PID, so sandboxed code can target any PID allowed by ordinary Unix permissions. Exploitation requires code inside a Capsicum sandbox; same-user targets can be stopped or killed, while a sandboxed superuser process can signal any process.

The record

CVE
CVE-2026-45259
Published
Jun 27, 2026
Updated
Jun 27, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-266, T1489
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.3-RELEASE <p15
  2. Affected versionversion=14.4-RELEASE <p6
  3. Affected versionversion=15.0-RELEASE <p10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p15; version=14.4-RELEASE <p6; version=15.0-RELEASE <p10

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-266Incorrect Privilege Assignment
T1489Service Stop

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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