CVE intelligence and bounded remediation

CVE-2026-33471 — nimiq-block contains block primitives to be used in Nimiq's Rust implementation

Critical CVSS 9.6

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.

Severity
Critical
CVSS
9.6 (3.1)
Published
2026-04-22
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-20, CWE-190, CWE-345, CWE-1284

Affected products

  • nimiq / nimiq_proof-of-stake

Matched remediation archetype

Supply-chain, dependency, build, and update integrity

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace affected packages, source archives, build actions, plugins, installers, and updates from declared source to deployed artifact.
  • Confirm provenance, signatures or digests, namespace ownership, lockfile resolution, registry configuration, and build-runner trust boundaries.
  • Inventory direct, transitive, vendored, generated, and bundled copies across releases and distribution channels.

Remediate safely

  • Move to a maintained trusted artifact or remove the dependency; pin immutable identities and verify provenance and integrity before use.
  • Regenerate lockfiles and artifacts in a clean isolated build, minimize build credentials and network access, and produce an updated software bill of materials.
  • Require reviewed update policy, protected publishing, and reproducible or independently attestable builds where supported.

Authoritative sources

Complete CVE record and remediation plan

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