Heap-based buffer overflow in FreeBSD - CVE-2026-42512
Published: April 30, 2026
Vulnerability identifier: #VU128487
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-42512
CWE-ID: CWE-122
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vendor: FreeBSD Foundation
Affected software:
FreeBSD
FreeBSD
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code or cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in dhclient when processing a crafted DHCP offer while building environment entries for dhclient-script. A remote attacker can send a specially crafted DHCP packet to execute arbitrary code or cause a denial of service.
Exploitation requires the attacker to be on the same broadcast domain and able to respond to DHCP requests.
How to mitigate CVE-2026-42512
Install security update from vendor's website.