CVE-2026-49866 PUBLISHED

libp2p is a JavaScript Implementation of libp2p networking stack. Prior to 16.0.0, @libp2p/gossipsub defaultDecodeRpcLimits set maxIhaveMessageIDs and maxIwantMessageIDs to Infinity, allowing oversized IHAVE and IWANT control message arrays in message/decodeRpc.ts and gossipsub.ts to synchronously iterate roughly 180,000 message IDs per 4 MB frame and block the Node.js event loop. This issue is fixed in version 16.0.0.

• https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv
• https://github.com/libp2p/js-libp2p/pull/3520
• https://github.com/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899
• https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0

• CWE-770: Allocation of Resources Without Limits or Throttling CWE