How broadly exploitable is this vulnerability?

Exploitation requires the ability to influence or submit `SkipBlockProof` structures that are accepted by honest nodes. In practice, this typically means an attacker must participate in the consensus protocol (e.g., as a validator or equivalent actor) or compromise a component that constructs proofs. It is not a generic remote code execution issue, but it can meaningfully affect consensus safety.

What level of access does an attacker need to exploit this?

The attacker must be able to craft and present skip block proofs with arbitrary `MultiSignature.signers` bitsets that are then processed by `SkipBlockProof::verify`. This usually implies protocol-level access rather than end-user access; for example, being a validator, controlling a node implementation, or interfering with the network path that supplies proofs.

What is the safest general fix pattern for this type of bug?

The safest pattern is to enforce strict validation and consistency checks on all signer indices and associated metadata before they influence quorum calculations. This includes: - Rejecting any index outside the expected validator set range. - Using checked integer conversions instead of lossy casts. - Ensuring each counted signer is uniquely mapped to a valid validator slot. Combined, these measures prevent index manipulation and make later verification logic simpler and more trustworthy.

Severity:

CRITICAL RISK

(9.6)

Quorum Verification Bypass via Integer Truncation (CWE-190, CWE-20) in Nimiq Skip Block Proofs

CVE-2026-33471

Published:

Apr 22, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-74;CWE-89

HIGH RISK

HIGH

(7.3)

SQL Injection via Unsanitized ID Parameter (CWE-89) in Pharmacy Sales and Inventory System /ajax.php

Database Compromise and Data Integrity Loss

April 27, 2026

CWE-863

HIGH RISK

HIGH

(8.5)

Incorrect Authorization (CWE-863) in OpenClaw chat.send Session Management

Privilege Escalation and Unauthorized Session Control

April 27, 2026

Vulnerability Type

Category:

Quorum / Signature Verification Bypass

CWE:

CWE-20;CWE-190;CWE-345;CWE-1284

Impact:

Consensus Integrity Compromise / Forged Quorum Proofs

Severity:

CRITICAL RISK

(9.6)

CVSS Version:

3.1

Vulnerability Type

Category:

Quorum / Signature Verification Bypass

CWE:

CWE-20;CWE-190;CWE-345;CWE-1284

Impact:

Consensus Integrity Compromise / Forged Quorum Proofs

Severity:

CRITICAL RISK

(9.6)

CVSS Version:

3.1

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Ask AI for summary of CodeAnt

Quorum Verification Bypass via Integer Truncation (CWE-190, CWE-20) in Nimiq Skip Block Proofs

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

SQL Injection via Unsanitized ID Parameter (CWE-89) in Pharmacy Sales and Inventory System /ajax.php

HIGH RISK

HIGH

(8.5)

Incorrect Authorization (CWE-863) in OpenClaw chat.send Session Management

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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