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TI-2026-25867 Aliases CVE-2026-33471GHSA-6973-8887-87ff

nimiq-block has skip block quorum bypass via out-of-range BitSet indices & u16 truncation

Priority MEDIUM 41CWE-1284Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-345.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00217 12th percentileScored 2026-11-07
Fix Fixed nimiq-block (nimiq): 1.3.0nimiq-block (crates.io): 1.7.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nimiqnimiq-blockbefore 1.3.01.3.0Patch availableCNA
—nimiq-block (crates.io)before 1.7.21.7.2Patch availableGHSA-6973-8887-87ff
  • nimiq-block Vendornimiq Affected before 1.3.0 Fixed in 1.3.0 Patch available CNA
  • nimiq-block (crates.io) Vendor— Affected before 1.7.2 Fixed in 1.7.2 Patch available GHSA-6973-8887-87ff

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nimiq:nimiq_proof-of-stake:*:*:*:*:*:rust:*:*before 1.3.0Vulnerablenimiq
  • cpe:2.3:a:nimiq:nimiq_proof-of-stake:*:*:*:*:*:rust:*:* Versions before 1.3.0 Vulnerable ·nimiq

Remediation

  • Fix · CNA nimiq-block (nimiq) Fixed in 1.3.0
  • Fix · GHSA-6973-8887-87ff nimiq-block (crates.io) Fixed in 1.7.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33471
  2. 2026-10-03 Alias added: GHSA-6973-8887-87ff
  3. 2026-10-30 Fix available: crates.io/[email protected] · GHSA-6973-8887-87ff

References

Patch 2

Advisory 1

Other 3

  • TI-2026-26389 nimiq-account: Vesting insufficient funds error can panic CVSS 3.1HIGH 8.2
  • TI-2026-27598 nimiq/core-rs-albatross: Panic in history index request handlers when a full node runs without the history index CVSS 3.1HIGH 7.5
  • TI-2026-26390 nimiq-primitives: Node crash due to missing interlink validation in election macro block proposals CVSS 3.1HIGH 7.5
  • TI-2026-26388 network-libp2p: Peer can crash the node by opening discovery protocol substream twice CVSS 3.1HIGH 7.5
  • TI-2026-25612 nimiq/core-rs-albatross: Discovery handshake limit could underflow and later provoke a deterministic overflow panic CVSS 3.1HIGH 7.5
  • TI-2026-25114 Nimiq: Remote crash via off-by-one signer bounds check in proposal buffer CVSS 3.1HIGH 7.5
See all 14 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences