How severe is CVE-2026-46543?

CVE-2026-46543 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-46543?

CVE-2026-46543 affects the following packages: nimiq-blockchain (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2026-46543?

Update nimiq-blockchain to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-46543 is resolved across your whole dependency graph.

How do I detect CVE-2026-46543 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nimiq-blockchain, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-46543 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-46543 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-46543 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-46543?

CVE-2026-46543 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 41th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-46543?

CVE-2026-46543 is classified as Reachable Assertion (CWE-617). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-46543 published, and has it been updated?

CVE-2026-46543 was published on June 9, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

MEDIUM severity

CVE-2026-46543 — nimiq-blockchain

MEDIUMFix: nimiq/core-rs-albatross#3745

CVE-2026-46543 is a medium-severity (CVSS 5.3) Reachable Assertion vulnerability in nimiq-blockchain. A fix is available for nimiq-blockchain — see the affected versions and patch details below.

nimiq-blockchain: Genesis batch set request

Also known asGHSA-vghx-352f-93jm

Published

Jun 9, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-46543.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs41th percentile — riskier than 41% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-46543 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 382,205 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🦀nimiq-blockchain

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Impact

A remote peer can crash any full node by sending a RequestBatchSet message containing the genesis block's hash. The handler calls get_epoch_chunks which iterates backwards through macro blocks using Policy::macro_block_before. When it reaches the genesis block number, macro_block_before panics with "No macro blocks before genesis block".

Patches

The patch for this vulnerability is formally released as part of v1.5.0.

Workarounds

No Workaround, although requesting the genesis batch set is not used during normal operation.

Resources

See PR.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`nimiq-blockchain`	all versions	1.5.0`cargo update -p nimiq-blockchain --precise 1.5.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nimiq-blockchain, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nimiq-blockchain to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-46543 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact A remote peer can crash any full node by sending a RequestBatchSet message containing the genesis block's hash. The handler calls `get_epoch_chunks` which iterates backwards through macro blocks using `Policy::macro_block_before`. When it reaches the genesis block number, `macro_block_before` panics with "No macro blocks before genesis block". ### Patches [The patch for this vulnerability](https://github.com/nimiq/core-rs-albatross/pull/3745) is formally released as part of [v1.5.0](https://github.com/nimiq/core-rs-albatross/releases/tag/v1.5.0). ### Workarounds No Workaround, alt