Answer in brief
CVE-2026-33471 records a Critical severity (CVSS 9.6) vulnerability in nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation. The current sources do not mark it as known exploited. The current feed maps nimiq-block (crates.io), nimiq-block (rust). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nimiq-block (crates.io), nimiq-block (rust). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:nimiq:nimiq_proof-of-stake:*:*:*:*:*:rust:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| nimiq-blockcrates.io | >=0 <1.7.2 | 1.7.2 |
| nimiq-blockrust | <1.3.0 | 1.7.2 |
Published upstream
Apr 22, 2026
Evidence: source:ghsa:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:ghsa:source_dates:source-dates:recordFirst seen by HOL
Oct 28, 2026
### Impact `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. 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. ### Patches [The patch for this vulnerability](https://github.com/nimiq/core-rs-albatross/pull/3657) is included as part of [v1.3.0](https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0). ### Workarounds No known workarounds.
Quoted source text, attributed separately from HOL analysis.