Quick answers
- Is CVE-2026-46540 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-46540 being exploited in the wild.
- How severe is CVE-2026-46540?
- Medium severity, with a CVSS score of 6.5, published 10 June 2026.
- Which products and versions are affected?
- Nimiq Albatross < 1.4.0.
- Is there a fix for CVE-2026-46540?
- A patch was published on 2026-04-22: Version 1.4.0 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-46540 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-46540?
- Check whether you run Nimiq Albatross at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A vulnerability exists in the `LightBlockchain::rebranch()` function of the Nimiq Rust implementation. When the client adopts a fork chain ending in a macro block (checkpoint or election), it updates the chain head but fails to update critical state variables including `macro_head`, `election_head`, and `current_validators`. This inconsistent state causes subsequent macro blocks to fail `verify_macro_successor()` checks and subsequent regular blocks to fail `verify_validators()` if the rebranch target was an election block. The resulting validation failures effectively stall the light client's chain progression. The issue is resolved in version 1.4.0 by ensuring all macro/election states are correctly synchronized during a rebranch.
Affected products
- Nimiq Nimiq Albatross (core-rs-albatross) < 1.4.0
Timeline
- 2026-04-22: patched: Version 1.4.0 released
- 2026-05-15: advisory: GitHub Security Advisory published
- 2026-06-10: disclosed: CVE published to NVD