CVE-2026-24785

CVE-2026-24785 is a critical-severity vulnerability in Jmlepisto Clatter with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-327.

Key facts

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.

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 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-24785 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-24785?
CVE-2026-24785 affects Jmlepisto Clatter. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-24785?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-24785 have an EU (EUVD) identifier?
Yes. CVE-2026-24785 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4896.
When was CVE-2026-24785 published?
CVE-2026-24785 was published on 2026-01-28 and last updated on 2026-06-17.

References

Affected products (1)

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