High severity · published Apr 30, 2026
CVE-2026-42511
Remote code execution via malicious DHCP options
8.1
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeBSD · FreeBSD
15.0-RELEASE before p7; 14.4-RELEASE before p3; 14.3-RELEASE before p12; 13.5-RELEASE before p13 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42511
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42511
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:12.dhclient.asc
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