CVE-2026-6507

A flaw was found in dnsmasq. A remote attacker could exploit an out-of-bounds write vulnerability by sending a specially crafted BOOTREPLY (Bootstrap Protocol Reply) packet to a dnsmasq server configured with the --dhcp-split-relay option. This can lead to memory corruption, causing the dnsmasq daemon to crash and resulting in a denial of service (DoS).

This vulnerability is rated Moderate rather than Important because exploitation is limited to a service crash and requires a non-standard configuration that is not enabled by default. The issue only affects dnsmasq instances explicitly configured to act as a DHCP split relay via the dhcp-split-relay option. Systems running dnsmasq with default settings, local DNS caching, or standard DHCP server roles are not susceptible to this flaw.

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.