CVE-2026-34069: nimiq-consensus panics via RequestMacroChain micro-block locator

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-14 · updated 2026-10-26
Weakness: CWE-617

Description

nimiq/core-rs-albatross is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. In versions 1.2.2 and below, an unauthenticated p2p peer can cause the RequestMacroChain message handler task to panic. Sending a RequestMacroChain message where the first locator hash on the victim’s main chain is a micro block hash (not a macro block hash) causes said panic. The RequestMacroChain::handle handler selects the locator based only on "is on main chain", then calls get_macro_blocks() and panics via .unwrap() when the selected hash is not a macro block (BlockchainError::BlockIsNotMacro). This issue has been fixed in version 1.3.0.

Affected products

nimiq-transaction: before 1.3.0 — fixed in 1.3.0

How to fix

Upgrade to a fixed version: nimiq-transaction 1.3.0. Check the vendor advisory for mitigations.

References

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