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

Q: How do I fix CVE-2026-33471?

nimiq proof-of-stake: upgrade to 1.3.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-33471 being exploited?

CVE-2026-33471 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-33471 affect?

CVE-2026-33471 affects nimiq proof-of-stake. Severity is 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`) f

Q: How urgent is CVE-2026-33471?

Priority 37/100. Critical severity

This month

CRITICAL 9.6UPGRADE

CVE-2026-33471 is a critical-severity flaw (CVSS 9.6) affecting nimiq proof-of-stake. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.6 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-20, CWE-190, CWE-345, CWE-1284
Published	2026-04-22
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: nimiq

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-22 20:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

nimiq nimiq proof-of-stake UPGRADE

Affected: < 1.3.0

Fixed in: 1.3.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nimiq-proof-of-stake || rpm -q nimiq-proof-of-stake || nimiq-proof-of-stake --version

2. UPGRADE to 1.3.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nimiq-proof-of-stake

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nimiq-proof-of-stake

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33471?

nimiq proof-of-stake: upgrade to 1.3.0. Exact commands for each OS are on this page.

Is CVE-2026-33471 being exploited?

CVE-2026-33471 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33471 affect?

CVE-2026-33471 affects nimiq proof-of-stake. Severity is 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`) f

How urgent is CVE-2026-33471?

Priority 37/100. Critical severity

Related CVEs

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References

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