VulnerabilityPublished 27 Jan 2026

CVE-2026-24785: jmlepisto clatter · Weak Cryptography

Affects jmlepisto clatterSource CVE Database V5

Not known to be exploited · CVSS 8.0 High : upgrade to 2.2.0 soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 4.0 base score

8.0High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.2.0

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

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: Unreported

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: Unreported: Based on threat intelligence sources each of the following must apply: · No knowledge of publicly available proof-of-concept · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade clatter and github/jmlepisto/clatter to 2.2.0.

Affected software

Product	Affected	Fixed in
jmlepistoclatter	Affected <2.2.0	Fixed in 2.2.0
crates.iogithub/jmlepisto/clatter`pkg:cargo/github/jmlepisto/clatter`Other threats	Affected <2.2.0	Fixed in 2.2.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade all Clatter library instances to version 2.2.0 or later, which includes runtime checks preventing insecure handshake patterns.
Immediately audit all usage of Noise protocol handshake patterns in your codebase, specifically identifying any use of `*_psk0` post-quantum variants and hybrid patterns.
Avoid using the vulnerable `noise_pqkk_psk0`, `noise_pqkn_psk0`, `noise_pqnk_psk0`, `noise_pqnn_psk0` handshake patterns entirely.
For custom handshake patterns, conduct a thorough cryptographic review to ensure compliance with the PSK validity rule (Noise Protocol Framework Section 9.3).
Implement network monitoring to detect anomalous handshake behavior or repeated key reuse attempts.
Engage cryptographic experts to validate the security of post-quantum handshake implementations in your environment.
Incorporate secure development lifecycle practices emphasizing cryptographic protocol compliance and regular dependency updates.
Coordinate with vendors and supply chain partners to confirm they have applied the patch or mitigations.
Consider additional layers of encryption or key management controls to mitigate potential exposure during transition.

Description

CVE-2026-24785 is a high-severity vulnerability in the Clatter Rust library, a no_std compatible implementation of the Noise protocol framework with post-quantum support. Versions prior to 2.2.0 allow the use of post-quantum handshake patterns that violate the PSK validity rule, enabling PSK-derived keys to be used without proper ephemeral randomness. This cryptographic flaw weakens security guarantees and risks catastrophic key reuse. The affected handshake patterns include several default `*_psk0` variants and some hybrid patterns. The issue is addressed in Clatter v2.2.0, which adds runtime checks to prevent insecure handshake patterns. Organizations using vulnerable versions and affected patterns may have compromised handshake security, risking confidentiality and integrity of communications.

Impact

For European organizations, the vulnerability poses a significant risk to the confidentiality and integrity of communications secured using the Clatter library with affected handshake patterns. Since Clatter is designed for no_std Rust environments and supports post-quantum cryptography, it is likely used in embedded systems, IoT devices, or security-sensitive applications adopting next-generation cryptographic protocols. Exploitation could lead to catastrophic key reuse, allowing attackers to decrypt or manipulate encrypted communications, potentially compromising sensitive data and critical infrastructure. This risk is heightened in sectors such as telecommunications, defense, finance, and critical infrastructure, where secure key exchange is paramount. The lack of required authentication or user interaction for exploitation increases the threat surface. Although no known exploits exist currently, the vulnerability's presence in cryptographic handshake protocols means that any interception or active man-in-the-middle attacks could be devastating. European organizations adopting post-quantum cryptography must be vigilant to prevent undermining their security posture due to this flaw.

CWE-327Use of a Broken or Risky Cryptographic Algorithm (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a broken or risky cryptographic algorithm or protocol.
Architecture and Design · Libraries or Frameworks
When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations.
Architecture and Design
Ensure that the design allows one cryptographic algorithm to be replaced with another in the next generation or version. Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms.
Architecture and Design
Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.
OWASP Cheat Sheets
Cryptographic Storage (opens in a new tab)
Key Management (opens in a new tab)
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.7 (opens in a new tab)
V2.9.3 (opens in a new tab)
V6.2.2 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoof (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
Cryptanalysis of Cellular Encryption (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Feb 2026, 09:25 UTC

WeaknessesCWE-327

Technical details

References

Community reviews

Related threats