---
title: "CVE-2026-40093: nimiq-blockchain is missing a wall-clock upper bound on block timestamps"
url: https://erroneo.us/security/cve/CVE-2026-40093/
description: "CVE-2026-40093 (nimiq-blockchain (crates.io (Rust))): nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. In 1.3.0 and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-09
date_modified: 2026-04-14
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-40093"
kev: false
cvss: 8.1
epss: 0.00434
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-40093: nimiq-blockchain is missing a wall-clock upper bound on block timestamps

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 37: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 37% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes nimiq-blockchain (crates.io (Rust)) <= 1.3.0, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. In 1.3.0 and earlier, block timestamp validation enforces that timestamp >= parent.timestamp for non-skip blocks and timestamp == parent.timestamp + MINPRODUCERTIMEOUT for skip blocks, but there is no visible upper bound check against the wall clock. A malicious block-producing validator can set block timestamps arbitrarily far in the future. This directly affects reward calculations via Policy::supplyat() and batchdelay() in blockchain/src/reward.rs, inflating the monetary supply beyond the intended emission schedule.

## Affected packages

- crates.io (Rust) `nimiq-blockchain` <= 1.3.0 → fixed: none listed

## Affected products (CVE record)

- nimiq core-rs-albatross: <= 1.3.0

## Severity

- GitHub_M CVSS 3.1: 8.1 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.43% probability of exploitation activity in the next 30 days; percentile 37.

## Sources

- [GitHub Advisory GHSA-49xc-52mp-cc9j](https://github.com/advisories/GHSA-49xc-52mp-cc9j)
- [CVE.org record CVE-2026-40093](https://www.cve.org/CVERecord?id=CVE-2026-40093)
- [NVD entry CVE-2026-40093](https://nvd.nist.gov/vuln/detail/CVE-2026-40093)
- [github.com](https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-49xc-52mp-cc9j)

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Source page: https://erroneo.us/security/cve/CVE-2026-40093/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt