Out-of-bounds read in Dnsmasq - CVE-2026-5172
Published: May 12, 2026
Vulnerability identifier: #VU131141
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-5172
CWE-ID: CWE-125
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 cause a denial of service.
The vulnerability exists due to out-of-bounds read in extract_addresses() when parsing a DNS resource record with a falsified rdlen value. A remote attacker can send a specially crafted DNS packet to cause a denial of service.
The issue occurs because extract_name() can advance the record pointer past the calculated end of the resource record, causing the remaining-length calculation to underflow.
How to mitigate CVE-2026-5172
Install security update from vendor's website.