CVE-2026-5172

A heap out-of-bounds read vulnerability was discovered in dnsmasq's DNS response processing. The extract_addresses() function trusts the declared record data length (rdlen) without verifying that a subsequent call to extract_name() stays within the record boundary. A crafted DNS response with a mismatched rdlen causes the remaining-bytes calculation to underflow, resulting in a massive out-of-bounds read and process crash.

Red Hat rates this as Important. While this bug does not require any special dnsmasq configuration, the impact is limited to denial of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.