CVE-2026-46539

Description

Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.4.0, a logic flaw in BlockInclusionProof::is_block_proven causes the function to return true without performing any cryptographic verification when get_interlink_hops yields an empty hop list. This occurs when the target block is at the election block position immediately preceding the election head's epoch. An attacker providing transaction inclusion proofs can forge a MacroBlock header for that epoch position and have it accepted as "proven" without any hash or signature verification. This issue has been patched in version 1.4.0.

Is your site exposed to CVE-2026-46539?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.9

MEDIUM

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

EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.05%

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-345 CWE-345

References

Other References

https://github.com/nimiq/core-rs-albatross/pull/3705 https://github.com/nimiq/core-rs-albatross/releases/tag/v1.4.0 https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-799f-29jm-gr6c

Frequently Asked Questions

What is CVE-2026-46539? +

Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.4.0, a logic flaw in BlockInclusionProof::is_block_proven causes the function to return true without performing any cryptographic verification when get_interlink_hops yields an empty hop list. This occurs when the target block is at the election block position immediately preceding the election head's epoch. An attacker providing transaction inclusion proofs can forge a MacroBlock header for that epoch position and have it accepted as "proven" without any hash or signature verification. This issue has been patched in version 1.4.0. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-46539? +

CVE-2026-46539 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0015, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-46539? +

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.

Related Vulnerabilities

CVE-2026-45022

go-git is an extensible git implementation library written in pure Go. Prior to 5.19.0 and 6.0.0-alpha.3, go-git may parse malformed …

CVE-2026-42206

Roadiz is a polymorphic content management system based on a node system. Prior to versions 2.3.43, 2.5.45, 2.6.31, and 2.7.18, …

CVE-2026-47202

Kavita is a cross platform reading server. Prior to 0.9.0.2, an Improper Token validation flaw permits a remote and unauthenticated …

CVE-2025-21606

stats is a macOS system monitor in for the menu bar. The Stats application is vulnerable to a local privilege …

CVE-2025-25188

Hickory DNS is a Rust based DNS client, server, and resolver. A vulnerability present starting in version 0.8.0 and prior …

CVE-2025-52484

RISC Zero is a general computing platform based on zk-STARKs and the RISC-V microarchitecture. Due to a missing constraint in …