CVE-2026-34063 network-libp2p: Peer can crash the node by opening discovery protocol substream twice
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-34063?
CVE-2026-34063 is a high-severity vulnerability in nimiq network-libp2p, published on 22 Apr 2026.
Official description
Nimiq's network-libp2p is a Nimiq network implementation based on libp2p. Prior to version 1.3.0, `network-libp2p` discovery uses a libp2p `ConnectionHandler` state machine. the handler assumes there is at most one inbound and one outbound discovery substream per connection. if a remote peer opens/negotiate the discovery protocol substream a second time on the same connection, the handler hits a `panic!(\"Inbound already connected\")` / `panic!(\"Outbound already connected\")` path instead of failing closed. This causes a remote crash of the networking task (swarm), taking the node's p2p networking offline until restart. The patch for this vulnerability is formally released as part of v1.3.0. No known workarounds are available.
Weakness: CWE-617
Which versions are affected by CVE-2026-34063?
It affects 1 product.
Products include Nimiq Nimiq Proof-of-Stake.
How do I fix CVE-2026-34063?
No fix has been published for CVE-2026-34063 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-34063 being exploited?
There is no known exploitation of CVE-2026-34063 in the wild and no public exploit code.
Other vulnerabilities in nimiq network-libp2p
- CVE-2026-33471 nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation
- CVE-2026-40093 nimiq-blockchain is missing a wall-clock upper bound on block timestamps
- CVE-2026-34065 nimiq-primitives: Node crash due to missing interlink validation in election macro block proposals
- CVE-2026-32605 Nimiq: Remote crash via off-by-one signer bounds check in proposal buffer
- CVE-2026-33184 nimiq/core-rs-albatross: Discovery handshake limit could underflow and later provoke a deterministic overflow panic
Sources
Also known as GHSA-74hp-mhfx-m45h.