CVE-2026-5856 Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation

Contiki-NG's DNS/mDNS resolver skipname 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 attack...

CVE-2026-5856

Affected software/component: Contiki-NG DNS/mDNS resolver (os/services/resolv/resolv.c). Root cause: skip_name() walks DNS wire-format labels without a packet-boundary check; newdata() loops nquestions from attacker-controlled DNS header before validating the transaction ID, causing the function ...