CVE-2026-46369 Nimiq: Validity store off by one error
A remote attacker can replay signed transactions due to an off-by-one error in validity checks, causing double balance updates.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46369?
CVE-2026-46369 is a high-severity vulnerability in nimiq core-rs-albatross, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Through 1.5.0, the validity store uses a strict lower-bound comparison that expires a stored transaction too early relative to Transaction::is_valid_at, allowing a remote attacker to replay the same signed transaction during a blocks_per_batch minus one block window and cause the sender and recipient balances to be updated twice. This issue is fixed in version 1.5.1.
Which versions are affected by CVE-2026-46369?
2 open source packages ship an affected version, including nimiq-blockchain.
| Package | Affected | Fixed in |
|---|---|---|
nimiq-blockchain crates.io | All versions | 1.5.1 |
nimiq-blockchain crates.io | All versions | 1.5.1 |
How do I fix CVE-2026-46369?
Upgrade nimiq-blockchain to 1.5.1 or later.
Is CVE-2026-46369 being exploited?
There is no known exploitation of CVE-2026-46369 in the wild and no public exploit code.
Sources
Also known as GHSA-3763-qp59-59vf.