Missing Authorization in FreeBSD - CVE-2026-45256
Published: June 11, 2026
Vulnerability identifier: #VU134370
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-45256
CWE-ID: CWE-862
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: FreeBSD Foundation
Affected software:
FreeBSD
FreeBSD
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper access control in thr_kill2(2) when delivering signals to a specific thread. A local user can send signals to processes they are not permitted to signal to cause a denial of service.
The issue also bypasses jail boundary enforcement, allowing signaling across jails or from a jail to the host. Knowledge or brute-force discovery of process and thread IDs is sufficient for exploitation.
How to mitigate CVE-2026-45256
Install security update from vendor's website.