CVE-2026-24785: 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 prot...

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.

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS 4.0

8/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.12%

2.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-327

Affected Software

Vendor	Product	Versions
Jmlepisto	Clatter	< 2.2.0

References

https://github.com/jmlepisto/clatter/commit/b65ae6e9b8019bed5407771e21f89ddff17c5a71Patch
https://github.com/jmlepisto/clatter/security/advisories/GHSA-253q-9q78-63x4Mitigation, Vendor Advisory
https://noiseprotocol.org/noise.html#validity-ruleTechnical Description

Timeline

Published: Jan 28, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-24785?

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.

How severe is CVE-2026-24785?

CVE-2026-24785 has a CVSS score of 8/10 (HIGH severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.

How do I fix CVE-2026-24785?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.