CVE-2026-86039 libp2p: PeerStore accepts attacker-signed PeerRecords for a victim peer ID and stores certified attacker addresses
Attackers can poison the peer store with malicious addresses for victim peers, causing routing manipulation and connection failures in libp2p applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-86039?
CVE-2026-86039 is a high-severity vulnerability in js-libp2p, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-86039?
2 open source packages ship an affected version, including @libp2p/peer-store.
| Package | Affected | Fixed in |
|---|---|---|
@libp2p/peer-store npm | From 8.0.0 | 12.0.24 |
@libp2p/peer-store npm | From 8.0.0 | 12.0.24 |
How do I fix CVE-2026-86039?
Upgrade @libp2p/peer-store to 12.0.24 or later.
Is CVE-2026-86039 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86039 exists.
Sources
Also known as GHSA-vrf4-mx87-p53w.