CVE-2026-49866: CWE-770: Allocation of Resources Without Limits or Throttling in libp2p js-libp2p
CVE-2026-49866 is a high-severity vulnerability in the JavaScript libp2p networking stack (js-libp2p) prior to version 16.0.0. The issue arises because the default decoding limits for IHAVE and IWANT message ID arrays were set to Infinity, allowing excessively large control message arrays to be processed synchronously. This can cause the Node.js event loop to be blocked by iterating over roughly 180,000 message IDs in a 4 MB frame, resulting in a denial of service due to resource exhaustion. The vulnerability is fixed in version 16.0.0.
AI Analysis
Technical Summary
The vulnerability in js-libp2p versions before 16.0.0 involves the allocation of resources without limits or throttling (CWE-770). Specifically, the defaultDecodeRpcLimits configuration set maxIhaveMessageIDs and maxIwantMessageIDs to Infinity, enabling oversized IHAVE and IWANT control message arrays to be processed synchronously in message/decodeRpc.ts and gossipsub.ts. This leads to blocking of the Node.js event loop by iterating over approximately 180,000 message IDs per 4 MB frame, causing a denial of service condition. The issue is resolved in version 16.0.0 where these limits are presumably enforced.
Potential Impact
The vulnerability allows an attacker to cause a denial of service by sending oversized IHAVE and IWANT control message arrays, which block the Node.js event loop during synchronous processing. This results in service unavailability or degraded performance. There is no impact on confidentiality or integrity according to the CVSS vector.
Mitigation Recommendations
A fix is available in js-libp2p version 16.0.0. Users should upgrade to version 16.0.0 or later to mitigate this vulnerability. No other mitigation guidance is provided or necessary given the availability of the official fix.
CVE-2026-49866: CWE-770: Allocation of Resources Without Limits or Throttling in libp2p js-libp2p
Description
CVE-2026-49866 is a high-severity vulnerability in the JavaScript libp2p networking stack (js-libp2p) prior to version 16.0.0. The issue arises because the default decoding limits for IHAVE and IWANT message ID arrays were set to Infinity, allowing excessively large control message arrays to be processed synchronously. This can cause the Node.js event loop to be blocked by iterating over roughly 180,000 message IDs in a 4 MB frame, resulting in a denial of service due to resource exhaustion. The vulnerability is fixed in version 16.0.0.
CVSS v3.1
Score 7.5high
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in js-libp2p versions before 16.0.0 involves the allocation of resources without limits or throttling (CWE-770). Specifically, the defaultDecodeRpcLimits configuration set maxIhaveMessageIDs and maxIwantMessageIDs to Infinity, enabling oversized IHAVE and IWANT control message arrays to be processed synchronously in message/decodeRpc.ts and gossipsub.ts. This leads to blocking of the Node.js event loop by iterating over approximately 180,000 message IDs per 4 MB frame, causing a denial of service condition. The issue is resolved in version 16.0.0 where these limits are presumably enforced.
Potential Impact
The vulnerability allows an attacker to cause a denial of service by sending oversized IHAVE and IWANT control message arrays, which block the Node.js event loop during synchronous processing. This results in service unavailability or degraded performance. There is no impact on confidentiality or integrity according to the CVSS vector.
Mitigation Recommendations
A fix is available in js-libp2p version 16.0.0. Users should upgrade to version 16.0.0 or later to mitigate this vulnerability. No other mitigation guidance is provided or necessary given the availability of the official fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-01T22:03:19.641Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4ebdf5c9d9e3dbe3bf8afa
Added to database: 07/08/2026, 21:15:33 UTC
Last enriched: 07/08/2026, 21:28:38 UTC
Last updated: 07/08/2026, 21:28:38 UTC
Views: 2
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