CVE-2026-42512

Remotely triggerable out-of-bounds heap write in dhclient

State: Published
Severity: 8.1 High
Published: Apr 30, 2026
Updated: May 1, 2026
Reserved: Apr 28, 2026

Description

As dhclient is building an environment to pass to dhclient-script, it may need to resize the array of string pointers. The code which expands the array incorrectly calculates its new size when requesting memory, resulting in a heap buffer overrun.

A specially crafted packet can cause dhclient to overrun its buffer of environment entries. This can result in a crash, but it may be possible to leverage this bug to achieve remote code execution.

Scores

CVSS	Score	Vector	Source
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-122 Heap-based Buffer Overflow

Affected Products

Product	Versions
FreeBSDFreeBSD	15.0-RELEASE to before p7Affected 14.4-RELEASE to before p3Affected 14.3-RELEASE to before p12Affected 13.5-RELEASE to before p13Affected

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:15.dhclient.ascvendor-advisory

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