CVE-2026-40093: Nimiq blockchain Nimiq-blockchain Is Missing A Wall-clock Vulnerability

CRITICAL
Advisory Identifier: GHSA-49xc-52mp-cc9j
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CVSS 9.1
CWE-1284 CWE-20
Published
Advisory Summary

CVE-2026-40093 is a CRITICAL (CVSS 9.1) nimiq-blockchain is missing a wall-clock vulnerability (CWE-1284: Improper Validation of Specified Quantity in Input) affecting Nimiq blockchain libraries in the crates.io ecosystem. The issue involves nimiq-blockchain is missing a wall-clock upper bound on block timestamps. Remediation is available in the latest vendor maintenance releases.

CVE-2026-40093 at a Glance

CVE Identifier CVE-2026-40093
GHSA Identifier GHSA-49xc-52mp-cc9j
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-1284: Improper Validation of Specified Quantity in Input
Affected Product Nimiq blockchain
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-40093

To remediate this vulnerability, upgrade all affected Nimiq blockchain dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

nimiq-blockchain fixed: Latest secure release 
Upgrade nimiq-blockchain to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for nimiq-blockchain

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-40093, inspect your project dependencies for Nimiq blockchain:

inspect dependencies for nimiq-blockchain

Analyze the terminal output to locate any version of Nimiq blockchain in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1284: Improper Validation of Specified Quantity in Input, where the product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties. In Nimiq blockchain, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Block timestamp validation enforces that `timestamp >= parent.timestamp` for non-skip blocks and `timestamp == parent.timestamp + MIN_PRODUCER_TIMEOUT` 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::supply_at()` and `batch_delay()` in `blockchain/src/reward.rs`, inflating the monetary supply beyond the intended emission schedule. ### Patches TBD ### Workarounds No know workarounds.

CVE-2026-40093 Affected Nimiq blockchain Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
nimiq-blockchain
 crates.io
≤ 1.3.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-49xc-52mp-cc9j
NVD — CVE-2026-40093 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40093
Nimiq blockchain Source Repository REPOSITORY
https://github.com/nimiq/core-rs-albatross

Frequently Asked Questions

What is CVE-2026-40093?
CVE-2026-40093 is a security vulnerability in Nimiq blockchain involving nimiq-blockchain is missing a wall-clock upper bound on block timestamps under CWE-1284: Improper Validation of Specified Quantity in Input.
Which Nimiq blockchain versions are affected?
Affected versions include releases prior to current release patches across affected packages: nimiq-blockchain.
What version fixes CVE-2026-40093?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is nimiq-blockchain affected?
Yes, nimiq-blockchain is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-40093?
CVE-2026-40093 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
What CWE is associated with CVE-2026-40093?
CVE-2026-40093 is classified under CWE-1284: Improper Validation of Specified Quantity in Input (The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.).
How can I check crates.io dependencies for CVE-2026-40093?
Run the dependency tree command: 'inspect dependencies for nimiq-blockchain'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-49xc-52mp-cc9j",
  "modified" : "2026-04-10T19:55:04Z",
  "published" : "2026-04-10T19:55:04Z",
  "aliases" : [ "CVE-2026-40093" ],
  "summary" : "nimiq-blockchain is missing a wall-clock upper bound on block timestamps",
  "details" : "### Impact\n\nBlock timestamp validation enforces that `timestamp >= parent.timestamp` for non-skip blocks and `timestamp == parent.timestamp + MIN_PRODUCER_TIMEOUT` 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::supply_at()` and `batch_delay()` in `blockchain/src/reward.rs`, inflating the monetary supply beyond the intended emission schedule.\n\n### Patches\nTBD\n\n### Workarounds\nNo know workarounds.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "nimiq-blockchain"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-49xc-52mp-cc9j"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40093"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nimiq/core-rs-albatross"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1284", "CWE-20" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-10T19:55:04Z",
    "nvd_published_at" : "2026-04-09T21:16:11Z"
  }
}