CVE-2026-49866 json
libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays
published 4mo ago modified 17d ago also EUVD-2026-42409 , GHSA-cwc9-cp4j-mcvv
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 50%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm @libp2p/gossipsub 16.0.0
- protocol libp2p-gossipsub 16.0.0
- protocol libp2p 16.0.0
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4mo ago
Exploit prediction
0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @libp2p/gossipsub | <16.0.0 |
16.0.0 |
Affected products
- libp2p js-libp2p
Classification
References
-
github.com
/libp2p/js-libp2p/pull/3520
web
-
github.com
/libp2p/js-libp2p/commit/773dd80ded24dbd6b19e675c89fd2f3b45f2d899
web
-
github.com
/libp2p/js-libp2p/security/advisories/GHSA-cwc9-cp4j-mcvv
web
-
github.com
/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.0
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-49866
advisory
-
github.com
/libp2p/js-libp2p
package
Sources
- CVE List CVE-2026-49866
- GitHub Advisory GHSA-cwc9-cp4j-mcvv
- NVD CVE-2026-49866
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.