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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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
Which versions are affected by CVE-2026-40092?
2 open source packages ship an affected version, including nimiq-keys.
| Package | 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.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-40092 being exploited?
There is no known exploitation of CVE-2026-40092 in the wild and no public exploit code.
Sources
Also known as GHSA-27w2-87xv-37c6.