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

> A malicious peer can crash Nimiq full nodes by sending a DHT record with an invalid Ed25519 signature length, causing a panic.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 May 2026
- **Updated:** 21 May 2026
- **Also known as:** GHSA-27w2-87xv-37c6

## What is CVE-2026-40092?

CVE-2026-40092 is a high-severity denial of service vulnerability in nimiq core-rs-albatross, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-252 (Unchecked Return Value)

## Which versions are affected by CVE-2026-40092?

2 open source packages ship an affected version, including nimiq-keys.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nimiq-keys` | crates.io | All versions to 0.2.0 | None |
| `nimiq-keys` | crates.io | All versions to 0.2.0 | None |

## How do I fix CVE-2026-40092?

No fix has been published for CVE-2026-40092 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40092 being exploited?

There is no known exploitation of CVE-2026-40092 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40092 and fix it if it is affected.

What it is: CVE-2026-40092 is a high-severity denial of service vulnerability in nimiq core-rs-albatross, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40092 in the wild and no public exploit code.

Affected packages and fixed versions:
- nimiq-keys (crates.io): affected all versions up to 0.2.0; no fix listed
- nimiq-keys (crates.io): affected all versions up to 0.2.0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-40092/ (Markdown: https://insights.sbomify.com/CVE-2026-40092/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40092
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40092
- OSV: https://osv.dev/vulnerability/CVE-2026-40092

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40092/
Summaries are generated and may contain mistakes; the official description above is the record.