Stack-based buffer overflow in FreeBSD - CVE-2026-39461
Published: May 21, 2026
Vulnerability identifier: #VU132010
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-39461
CWE-ID: CWE-121
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 escalate privileges.
The vulnerability exists due to stack-based buffer overflow in libcasper when handling socket descriptors that exceed select(2) descriptor set limits. A local user can cause an application using libcasper to allocate large file descriptors to escalate privileges.
Exploitation requires a target application that uses libcasper, and privilege escalation is possible if that application runs with setuid root privileges.
How to mitigate CVE-2026-39461
Install security update from vendor's website.