CVE-2026-49866
Full vulnerability record from the local CVENow database.
Description
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.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Deferred
Source identifier
Published
2026-07-08 21:16:49.137000
Last modified
2026-10-25 17:10:00.197000
View original CVE JSON
{
"id": "CVE-2026-49866",
"sourceIdentifier": "[email protected]",
"published": "2026-07-08T21:16:49.137",
"lastModified": "2026-10-25T17:10:00.197",
"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."
},
{
"lang": "es",
"value": "libp2p es una Implementación de JavaScript de la pila de red de libp2p. Antes de la versión 16.0.0, @libp2p/gossipsub defaultDecodeRpcLimits estableció maxIhaveMessageIDs y maxIwantMessageIDs en Infinito, permitiendo que los arrays de mensajes de control IHAVE e IWANT sobredimensionados en message/decodeRpc.ts y gossipsub.ts iteraran sincrónicamente aproximadamente 180.000 IDs de mensaje por trama de 4 MB y bloquearan el bucle de eventos de Node.js. Este problema está solucionado en la versión 16.0.0."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "libp2p",
"product": "js-libp2p",
"versions": [
{
"version": "< 16.0.0",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"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": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-770"
}
]
}
],
"references": [
{
"url": "https://github.com/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899",
"source": "[email protected]"
},
{
"url": "https://github.com/libp2p/js-libp2p/pull/3520",
"source": "[email protected]"
},
{
"url": "https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0",
"source": "[email protected]"
},
{
"url": "https://github.com/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv",
"source": "[email protected]"
}
]
}