CVSS7.1
Severityhigh
WeaknessCWE-125
ExploitedNot in CISA KEV
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
Description
Contiki-NG's DNS/mDNS resolver skip_name() in os/services/resolv/resolv.c walks DNS wire-format name labels with no packet-boundary check, and the caller in newdata() invokes it in a loop iterating nquestions times from the attacker-controlled DNS header before validating the transaction ID. An attacker who sets nquestions higher than the number of complete questions present causes skip_name() to walk past the UDP packet buffer, and the returned pointer is cast to struct dns_answer * for further memory reads. On builds with RESOLV_CONF_SUPPORTS_MDNS enabled, any peer on the local segment can trigger the read unauthenticated via a multicast UDP 5353 packet with no outstanding query required;