CVE-2026-12969

An out-of-bounds read vulnerability exists in dnsmasq's find_soa() function in src/rfc1035.c. When parsing NS section records, extract_name() is called with extrabytes=0, failing to validate that 10 additional bytes exist for fixed-length DNS record fields. A remote attacker controlling a DNS zone can exploit this via a crafted NXDOMAIN response to cause a 10-byte heap out-of-bounds read, potentially accessing stale data from prior transactions.

Red Hat rates this issue as Low impact. While the vulnerability is remotely triggerable without authentication, the 10-byte out-of-bounds read stays within the over-allocated packet buffer in default dnsmasq configurations (1035 bytes of headroom beyond the logical packet boundary). A crash is not achievable in practice, and the potential information disclosure is limited to stale heap data within the same buffer allocation. The fix is available in dnsmasq 2.93rc1 and later.

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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. The fix is available in dnsmasq 2.93rc1 and later.