select(2) file descriptor set overflow causes stack overflow_CVE-2026-39461

5.1 / 10

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

Description

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.

Basic Information

ID CVE-2026-39461

Source freebsd

Published May 21, 2026 at 09:20

Modified May 21, 2026 at 12:25

Affected Product

Vendor FreeBSD

Product FreeBSD

Version 15.0-RELEASE

Affected Versions FreeBSD FreeBSD 15.0-RELEASE
FreeBSD FreeBSD 14.4-RELEASE
FreeBSD FreeBSD 14.3-RELEASE

CWE Classification

CWE-121

References

security.freebsd.org /advisories/FreeBSD-SA-26:22.libcasper.asc

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    "published": "2026-05-21T09:20:26.126Z",
    "modified": "2026-05-21T12:25:47.575Z",
    "type": "cve",
    "title": "select(2) file descriptor set overflow causes stack overflow",
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