CVE-2026-46369: Nimiq: Validity store off by one error

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-26 · updated 2026-09-09
Weakness: CWE-193

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.

Affected products

nimiq core-rs-albatross: before 1.5.1

References

https://github.com/nimiq/core-rs-albatross/commit/a530b2434ebca6e3716f07c73079786fcc6f2e41
https://github.com/nimiq/core-rs-albatross/pull/3772
https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-3763-qp59-59vf

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