CVE-2026-2291

Name of the Vulnerable Software and Affected Versions dnsmasq versions 2.73 through 2.92

Description A heap buffer overflow exists in the DNS cache when processing DNS responses. The extract name() function can be abused because the software expands certain characters into longer escape sequences without ensuring the cache buffer is sized to hold the expanded result. Specifically, an unsafe strcpy() in the really insert() function within src/cache.c copies attacker-controlled name strings without bounds validation, overflowing a 1,025-byte bigname cache buffer. An attacker can exploit this by using a malicious upstream DNS server and crafted CNAME chains to corrupt memory, potentially leading to remote code execution, DNS cache poisoning to redirect lookups to attacker-controlled IP addresses, or a denial of service (DoS).

Recommendations Update dnsmasq to version 2.92rel2 or 2.93.