Stack-based buffer overflow in FreeBSD - CVE-2026-39457
Published: April 30, 2026
Vulnerability identifier: #VU128488
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-39457
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 a stack-based buffer overflow in libnv when exchanging data over a socket using a socket descriptor that exceeds FD_SETSIZE. A local user can force a libnv application to allocate large file descriptors to escalate privileges.
If the target application is setuid-root, successful exploitation could result in privilege escalation.
How to mitigate CVE-2026-39457
Install security update from vendor's website.