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Fencer Vulns
high 8.2

CVE-2026-86039 json

libp2p: PeerStore accepts attacker-signed PeerRecords for a victim peer ID and stores certified attacker addresses

published 2026-09-17 53 d ago modified 2026-09-24 45 d ago also EUVD-2026-81686 , GHSA-vrf4-mx87-p53w

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

libp2p is a JavaScript implementation of the libp2p networking stack. From 8.0.0 until 12.0.24, @libp2p/peer-store in packages/peer-store/src/index.ts uses consumePeerRecord to verify a RecordEnvelope signature but does not require PeerRecord.peerId in the signed payload to equal the signer peer ID derived by RecordEnvelope.openAndCertify. The expectedPeer option checks only the envelope signer, and the gossipsub Peer Exchange path can provide the attacker's own peer ID as expectedPeer. An attacker can therefore sign a record with the attacker's key, place a victim peer ID and attacker-controlled multiaddrs in the payload, and have certified addresses stored for the victim. The poisoned addresses can cause address-book corruption, dial redirection or failure, routing manipulation, and reachability disruption, although the connection upgrade still verifies remote peer identity and prevents a complete identity takeover. The issue is fixed in version 12.0.24.

Patch / fix

  • npm @libp2p/peer-store 12.0.24
  • protocol libp2p 12.0.24

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
48 d ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/libp2p/js-libp2p/security/advisories/GHSA-vrf4-mx87-p53w referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
GitHub 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

Affected packages

ecosystem package affected fixed in
npm @libp2p/peer-store
>=8.0.0, <12.0.24
12.0.24

Affected products

  • libp2p js-libp2p

Classification

Weakness
  • CWE-290 Authentication Bypass by Spoofing
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns 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.