CVE-2026-498667.5HighCWE-770

CVE-2026-49866: libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays

libp2p · js-libp2p

Affected: libp2p js-libp2p · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.6%probability of exploitation in the next 30 days

50th percentile

050100

Higher than 50% of scored CVEs

7.5HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

libp2p · js-libp2p< 16.0.0

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Allocation Without Limits · Denial of Service
Vendor: libp2p
Published: July 2026
Band: Unlikely (under 1%), July 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-49866 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.