Nimiq: Validity store off by one error

Answer in brief

CVE-2026-46369 records a High severity (CVSS 7.5) vulnerability in Nimiq: Validity store off by one error. The current sources do not mark it as known exploited. The current feed maps nimiq-blockchain (crates.io), nimiq/core-rs-albatross (generic), nimiq-blockchain (rust). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 12, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps nimiq-blockchain (crates.io), nimiq/core-rs-albatross (generic), nimiq-blockchain (rust). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
nimiq-blockchaincrates.io	>=0 <1.5.1	1.5.1
nimiq/core-rs-albatrossgeneric	< 1.5.1	Not reported
nimiq-blockchainrust	<=1.5.0	1.5.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for nimiq-blockchain, nimiq/core-rs-albatross, nimiq-blockchain.
Review the reported fix. Update nimiq-blockchain to 1.5.1; nimiq-blockchain to 1.5.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 12, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.