CVE-2026-39457

CVE-2026-39457: Stack overflow via select() file descriptor set overflow

Vendor Freebsd
Product FreeBSD
Weakness CWE-121
Published April 30, 2026
Last update May 1, 2026

CVSS base score

What the vulnerability does

01Description

When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, can trigger stack corruption. If the target application is setuid-root, then this could be used to elevate local privileges.

Key dates

02Disclosure timeline

April 30, 2026 CVE published
May 1, 2026 Record updated