nimiq-block contains block primitives to be used in Nimiq's Rust implementation. `SkipBlockProof::verify` computes its quorum check using `BitSet.len()`, then iterates `BitSet` indices and casts each `usize` index to `u16` (`slot as u16`) for slot lookup. Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-6973-8887-87ff | nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 24 Apr 2026 17:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Nimiq
Nimiq nimiq Proof-of-stake |
|
| CPEs | cpe:2.3:a:nimiq:nimiq_proof-of-stake:*:*:*:*:*:rust:*:* | |
| Vendors & Products |
Nimiq
Nimiq nimiq Proof-of-stake |
Thu, 23 Apr 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 22 Apr 2026 20:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | nimiq/core-rs-albatross is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. `SkipBlockProof::verify` computes its quorum check using `BitSet.len()`, then iterates `BitSet` indices and casts each `usize` index to `u16` (`slot as u16`) for slot lookup. Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available. | nimiq-block contains block primitives to be used in Nimiq's Rust implementation. `SkipBlockProof::verify` computes its quorum check using `BitSet.len()`, then iterates `BitSet` indices and casts each `usize` index to `u16` (`slot as u16`) for slot lookup. Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available. |
Wed, 22 Apr 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | nimiq/core-rs-albatross is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. `SkipBlockProof::verify` computes its quorum check using `BitSet.len()`, then iterates `BitSet` indices and casts each `usize` index to `u16` (`slot as u16`) for slot lookup. Prior to version 1.3.0, if an attacker can get a `SkipBlockProof` verified where `MultiSignature.signers` contains out-of-range indices spaced by 65536, these indices inflate `len()` but collide onto the same in-range `u16` slot during aggregation. This makes it possible for a malicious validator with far fewer than `2f+1` real signer slots to pass skip block proof verification by multiplying a single BLS signature by the same factor. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available. | |
| Title | nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation | |
| Weaknesses | CWE-1284 CWE-190 CWE-20 CWE-345 |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-04-23T14:15:20.570Z
Reserved: 2026-03-20T16:16:48.969Z
Link: CVE-2026-33471
Vulnrichment
Updated: 2026-04-23T14:15:16.296Z
NVD
Status : Analyzed
Published: 2026-04-22T20:16:40.317
Modified: 2026-04-24T17:11:40.037
Link: CVE-2026-33471
Redhat
No data.
OpenCVE Enrichment
No data.