RUSTSEC-2026-0330 Hybrid Encapsulation from Seed Panics on Short Seed
An attacker can cause a denial of service by providing a short seed to the encapsulation function in libcrux-kem, triggering a panic.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is RUSTSEC-2026-0330?
RUSTSEC-2026-0330 is a denial of service vulnerability in libcrux-kem, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
For a hybrid KEM public key of type PublicKey::WingKemDraft06 or PublicKey::X25519MlKem768Draft06, the PublicKey::encapsulate_derand function would panic in an indexing operation on a seed input of length shorter than 32 bytes.
Impact
Applications encapsulating with an attacker controlled seed value could be made to panic. Since the encapsulation seed should be considered a secret of the encapsulating party for the KEM to remain secure, an application should never take the seed value from a potentially attacker controlled source.
Mitigation
With release of version 0.0.10 of libcrux-kem this bug has been fixed and the serialization functions return InvalidPrivateKey and InvalidPublicKey errors on invalid input buffer lengths.
We recommend users upgrade to libcrux-kem version 0.0.10.
Which versions are affected by RUSTSEC-2026-0330?
1 open source package ship an affected version, including libcrux-kem.
| Package | Affected | Fixed in |
|---|---|---|
libcrux-kem crates.io | From 0.0.0-0 | 0.0.10 |
How do I fix RUSTSEC-2026-0330?
Upgrade libcrux-kem to 0.0.10 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is RUSTSEC-2026-0330 being exploited?
There is no known exploitation of RUSTSEC-2026-0330 in the wild and no public exploit code.