Is CVE-2026-34066 actively exploited?

No active exploitation of CVE-2026-34066 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-34066 be exploited remotely?

Yes. CVE-2026-34066 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-34066?

CVE-2026-34066 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-34066

CWE-20Published: April 22, 2026· Updated: Apr 24, 2026

5.3

CVSS v3.1

EPSS:0.05%probability of exploitation in 30 daysPercentile:15.2th

Official Description

nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. Prior to version 1.3.0, `HistoryStore::put_historic_txns` uses an `assert!` to enforce invariants about `HistoricTransaction.block_number` (must be within the macro block being pushed and within the same epoch). During history sync, a peer can influence the `history: &[HistoricTransaction]` input passed into `Blockchain::push_history_sync`, and a malformed history list can violate these invariants and trigger a panic. `extend_history_sync` calls `this.history_store.add_to_history(..)` before comparing the computed history root against the macro block header (`block.history_root()`), so the panic can happen before later rejection checks run. The patch for this vulnerability is included as part of v1.3.0. No known workarounds are available.

NVD Source

Technical Analysis

CVE-2026-34066 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.3.