CVE-2026-34061 nimiq/core-rs-albatross: Macro block proposal interlink bug
A malicious validator can propose a macro block with an invalid interlink, causing honest validators to reject the finalized block and potentially halt consensus.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-34061?
CVE-2026-34061 is a medium-severity vulnerability in nimiq core-rs-albatross, published on 3 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
nimiq/core-rs-albatross is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.3.0, an elected validator proposer can send an election macro block whose header.interlink does not match the canonical next interlink. Honest validators accept that proposal in verify_macro_block_proposal() because the proposal path validates header shape, successor relation, proposer, body root, and state, but never checks the interlink binding for election blocks. The same finalized block is later rejected by verify_block() during push with InvalidInterlink. Because validators prevote and precommit the malformed header hash itself, the failure happens after Tendermint decides the block, not before voting. This issue has been patched in version 1.3.0.
Weakness: CWE-345
Which versions are affected by CVE-2026-34061?
It affects 1 product.
Products include Nimiq Nimiq Proof-of-Stake.
How do I fix CVE-2026-34061?
No fix has been published for CVE-2026-34061 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-34061 being exploited?
There is no known exploitation of CVE-2026-34061 in the wild and no public exploit code.
Other vulnerabilities in nimiq core-rs-albatross
- CVE-2026-33471 nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation
- CVE-2026-40093 nimiq-blockchain is missing a wall-clock upper bound on block timestamps
- CVE-2026-34063 network-libp2p: Peer can crash the node by opening discovery protocol substream twice
- CVE-2026-34065 nimiq-primitives: Node crash due to missing interlink validation in election macro block proposals
- CVE-2026-32605 Nimiq: Remote crash via off-by-one signer bounds check in proposal buffer
Sources
Also known as GHSA-gr83-j5f8-p2r5.