CVE-2026-45259
sigqueue(2) missing capability mode restriction
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.
INFO
Published Date :
June 27, 2026, 9:16 a.m.
Last Modified :
July 1, 2026, 2:04 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the system kernel and related security components.
- Verify sigqueue() respects capability mode restrictions.
- Test signal delivery for sandboxed processes.
- Reboot the system after applying updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45259.
| URL | Resource |
|---|---|
| https://security.freebsd.org/advisories/FreeBSD-SA-26:28.capsicum.asc | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45259 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45259
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45259 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45259 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 01, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p11:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p12:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p13:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p3:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p4:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p7:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p8:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.3:p14:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:14.4:p5:*:*:*:*:*:* *cpe:2.3:o:freebsd:freebsd:15.0:p9:*:*:*:*:*:* Added Reference Type FreeBSD: https://security.freebsd.org/advisories/FreeBSD-SA-26:28.capsicum.asc Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 29, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Added SSVC {'id': 'CVE-2026-45259', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-29T13:10:36.202760Z'} -
New CVE Received by [email protected]
Jun. 27, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'FreeBSD', 'modules': ['capsicum'], 'product': 'FreeBSD', 'versions': [{'status': 'affected', 'version': '15.0-RELEASE', 'lessThan': 'p10', 'versionType': 'release'}, {'status': 'affected', 'version': '14.4-RELEASE', 'lessThan': 'p6', 'versionType': 'release'}, {'status': 'affected', 'version': '14.3-RELEASE', 'lessThan': 'p15', 'versionType': 'release'}], 'defaultStatus': 'unknown'}] Added 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. Added CWE CWE-266 Added Reference https://security.freebsd.org/advisories/FreeBSD-SA-26:28.capsicum.asc