CVE-2026-24785 Clatter has a PSK Validity Rule Violation issue
Clatter library allowed PSK handshake patterns violating protocol rules, potentially enabling key reuse and weakening encryption security.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-24785?
CVE-2026-24785 is a high-severity vulnerability in jmlepisto clatter, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Clatter is a no_std compatible, pure Rust implementation of the Noise protocol framework with post-quantum support. Versiosn prior to2.2.0 have a protocol compliance vulnerability. The library allowed post-quantum handshake patterns that violated the PSK validity rule (Noise Protocol Framework Section 9.3). This could allow PSK-derived keys to be used for encryption without proper randomization by self-chosen ephemeral randomness, weakening security guarantees and potentially allowing catastrophic key reuse. Affected default patterns include `noise_pqkk_psk0`, `noise_pqkn_psk0`, `noise_pqnk_psk0`, `noise_pqnn_psk0``, and some hybrid variants. Users of these patterns may have been using handshakes that do not meet the intended security properties. The issue is fully patched and released in Clatter v2.2.0. The fixed version includes runtime checks to detect offending handshake patterns. As a workaround, avoid using offending `*_psk0` variants of post-quantum patterns. Review custom handshake patterns carefully.
Weakness: CWE-327
Which versions are affected by CVE-2026-24785?
2 open source packages ship an affected version, including clatter. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
clatter crates.io | All versions | 2.2.0 |
clatter crates.io | All versions | 2.2.0 |
Products include Jmlepisto Clatter.
How do I fix CVE-2026-24785?
Upgrade clatter to 2.2.0 or later.
Is CVE-2026-24785 being exploited?
There is no known exploitation of CVE-2026-24785 in the wild and no public exploit code.
Sources
Also known as GHSA-253q-9q78-63x4.