PT-2026-42397 · Freebsd · Freebsd

Joshua Rogers · Published 2026-05-21 · Updated 2026-05-21 · CVE-2026-39461

NVD

CVSS v3.1

5.1

Medium

Base vector

AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

libcasper(3) communicates with helper processes via UNIX domain sockets, and uses the select(2) system call to wait for data to become available. However, it does not verify that its socket descriptor fits within select(2)'s descriptor set size limit of FD SETSIZE (1024).

An attacker able to cause an application using libcasper(3) to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, may trigger stack corruption. If the target application runs with setuid root privileges, this could be used to escalate local privileges.

Fix

Stack Overflow

Weakness Enumeration

CWE-121

Related Identifiers

CVE-2026-39461

Affected Products

Freebsd

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-39461 · Security Note
• https://security.freebsd.org/advisories/FreeBSD-SA-26:22.libcasper.asc · Vendor Advisory
• https://reddit.com/r/freebsd/comments/1tjaceg/20260520_freebsd_errata_notice_and_seven_security · Reddit Post