CARGO · AUGUST 2026 · EARLY WARNING

nimiq-blockchain Package Vulnerability: Validity Store Off-by-One Error

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
nimiq-blockchain (cargo)
Affected versions
< 1.5.1 or <= 1.3.0 or <= 0.2.0 or < 1.5.0
Patched version
Not yet available
GHSA-3763-QP59-59VF

An early warning has been issued for a vulnerability in the nimiq-blockchain package. The issue is an off-by-one error in the validity store that could allow replay of signed transactions.

What happened

An off-by-one error has been identified in the nimiq-blockchain package's validity store. This error could potentially allow an attacker to replay the same signed transaction within a contiguous window of blocks. This could result in double debits and credits. The vulnerability is under investigation and has not yet been exploited in the wild.

The affected versions of nimiq-blockchain are those less than 1.5.1, or less than or equal to 1.3.0, or less than or equal to 0.2.0, or less than 1.5.0. Users of these versions are advised to assess their exposure and prepare for an upgrade once a patched version is released.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If nimiq-blockchain is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

You are affected if you are using nimiq-blockchain version less than 1.5.1, or less than or equal to 1.3.0, or less than or equal to 0.2.0, or less than 1.5.0.

What should I do right now?

Review your dependencies and prepare to upgrade to the patched version once it is released. Monitor the sources for updates.

When will the patched version be available?

The release date for the patched version is not yet known. Continue to monitor the sources for updates.

Sources

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