CVE-2026-34063

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-617 CWE-617

Affected Products

Vendor	Product	Versions
nimiq	nimiq_proof-of-stake	< 1.3.0

References

Advisories & Patches

https://github.com/nimiq/core-rs-albatross/commit/e0d4e01994f061bf41d3c2835bc74040d3c084f5 https://github.com/nimiq/core-rs-albatross/pull/3666 https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-74hp-mhfx-m45h

Other References

https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0

Frequently Asked Questions

What is CVE-2026-34063? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-34063? +

CVE-2026-34063 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-34063? +

CVE-2026-34063 affects products from nimiq, specifically: nimiq_proof-of-stake. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-34063? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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