# CVE-2026-34063

> Vulnerability · severity: **HIGH** (CVSS 7.5).

## 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.

## Key facts

- **CVE ID:** CVE-2026-34063
- **Published:** 2026-04-22
- **CVSS severity:** HIGH
- **CVSS base score:** 7.5
- **CWE codes:** CWE-617

## Affected products

- `nimiq:nimiq_proof-of-stake`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34063

## Citation

> AI Analytics. CVE-2026-34063. Retrieved 2026-07-17 from https://api.ai-analytics.org/cve/CVE-2026-34063. Derived from NIST NVD. Licensed CC0.

---

*[Dataset catalog](https://api.ai-analytics.org/datasets/) · [AI Analytics](https://api.ai-analytics.org/) · CC0 1.0*