{"id":"CVE-2026-49866","sourceIdentifier":"security-advisories@github.com","published":"2026-07-08T21:16:49.137","lastModified":"2026-07-10T19:10:59.333","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"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."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"libp2p","product":"js-libp2p","versions":[{"version":"< 16.0.0","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-09T14:37:59.412018Z","id":"CVE-2026-49866","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-770"}]}],"references":[{"url":"https://github.com/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899","source":"security-advisories@github.com"},{"url":"https://github.com/libp2p/js-libp2p/pull/3520","source":"security-advisories@github.com"},{"url":"https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0","source":"security-advisories@github.com"},{"url":"https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv","source":"security-advisories@github.com"}]}