CVE-2026-34066

nimiq-blockchain: Peer-triggerable panic during history sync

MEDIUM
5.3
CVSS Score
Published: April 22, 2026 at 07:47 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorNimiq Proof of Stake

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.3.0
Affected range stops below 1.3.0, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-20CWE-617CWE-754

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