Stack-based buffer overflow in Dnsmasq - CVE-2026-4892
Published: May 12, 2026
Vulnerability identifier: #VU131143
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/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-2026-4892
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: GNU
Affected software:
Dnsmasq
Dnsmasq
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to stack-based buffer overflow in helper.c when processing oversized DHCPv6 CLIDs for the --dhcp-script helper path. A remote attacker can send a specially crafted DHCPv6 client identifier to execute arbitrary code.
Only configurations with --dhcp-script enabled are vulnerable, and the helper process retains root privileges.
How to mitigate CVE-2026-4892
Install security update from vendor's website.