CVE-2026-42511

Remote code execution via malicious DHCP options

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

Description

The BOOTP file field is written to the lease file without escaping embedded double-quotes, allowing injection of arbitrary dhclient.conf directives. When the lease file is subsequently re-parsed by dhclient, e.g., after a system restart, an attacker-controlled field from the lease is passed to dhclient-script(8), which evaluates it.

A rogue DHCP server may be able to execute arbirary code as root on a system running dhclient.

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-149 Improper Neutralization of Quoting Syntax

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-26:12.dhclient.ascvendor-advisory

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