EUVD-2026-42409

libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays...

libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays

Summary gossipsub processes IHAVE and IWANT control messages by iterating every received message ID synchronously before doing anything with the results. There is no cap on how many IDs a single frame may contain. The default LP frame limit is 4MB, which fits roughly 180,000 message IDs. Iteratin...

CVE-2026-49866

CVE-2026-49866 affects the JavaScript libp2p implementation, specifically the @libp2p/gossipsub component. The root cause is defaultDecodeRpcLimits allowing maxIhaveMessageIDs and maxIwantMessageIDs to be Infinity prior to v16.0.0, enabling oversized IHAVE/IWANT control message arrays in message/...