CVE-2026-49866
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
Product@libp2p/gossipsub
PublishedJul 8, 2026
First seenJul 8, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Update
- @libp2p/gossipsub16.0.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| @libp2p/gossipsubnpm | v < 16.0.0 | 16.0.0 |
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