VulnerabilityPublished 28 Jan 2026

CVE-2026-24850: RustCrypto signatures · Improper Verification of Cryptographic Signature

Affects RustCrypto signaturesSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.1.0-rc.4 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.1.0-rc.4

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 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 RustCrypto signatures to 0.1.0-rc.4.

Affected software

Product	Affected	Fixed in
RustCryptosignatures	Affected >=0.0.4 <0.1.0-rc.4	Fixed in 0.1.0-rc.4

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

AI-suggested

To mitigate CVE-2026-24850, European organizations should immediately identify any usage of the RustCrypto ml-dsa crate versions >= 0.0.4 and < 0.1.0-rc.4 within their software stacks, especially in cryptographic signature verification components. The primary remediation is to upgrade to version 0.1.0-rc.4 or later, where the strict monotonic check for hint indices is correctly enforced. Organizations should audit their cryptographic implementations to ensure compliance with ML-DSA specifications and verify that no custom patches or forks reintroduce the vulnerability. Implementing additional signature validation layers or fuzz testing on signature inputs can help detect malformed signatures with duplicate indices. Security teams should monitor for suspicious signature verification failures or anomalies in logs that might indicate attempted exploitation. Incorporating cryptographic code reviews and automated static analysis tools focused on signature verification logic can prevent similar regressions. For critical systems, consider deploying runtime integrity checks or cryptographic hardware modules that enforce strict signature validation. Finally, maintain awareness of updates from RustCrypto and related cryptographic libraries to promptly apply security patches.

Description

CVE-2026-24850 is a medium severity vulnerability in the RustCrypto ml-dsa crate affecting versions from 0.0.4 up to but not including 0.1.0-rc.4. The issue arises from an improper verification of cryptographic signatures due to a regression bug where the strict ordering check for hint indices was changed from '<' to '<=', allowing duplicate indices. This violates the ML-DSA specification (FIPS 204 / RFC 9881) which requires strictly increasing indices, potentially enabling attackers to forge or manipulate signatures. The vulnerability impacts the integrity of signature verification but does not affect confidentiality or availability. No known exploits are reported in the wild.

Impact

The primary impact of CVE-2026-24850 is on the integrity of cryptographic signatures verified using the affected RustCrypto ml-dsa crate versions. By accepting signatures with duplicate hint indices, attackers can potentially forge signatures or bypass signature verification, leading to unauthorized actions, data manipulation, or the acceptance of malicious code or messages as legitimate. For European organizations, this can compromise software supply chains, secure communications, and authentication mechanisms relying on ML-DSA signatures implemented via this crate. Although confidentiality and availability are not directly affected, the loss of integrity can have cascading effects, such as unauthorized access, fraud, or disruption of trust in digital systems. The vulnerability is exploitable remotely without authentication or user interaction, increasing the risk profile. However, exploitation requires the attacker to craft signatures with specific malformed hint indices, which may limit widespread exploitation. The absence of known exploits in the wild suggests limited active targeting so far, but the medium severity score indicates a meaningful risk if the vulnerable versions are deployed in critical systems. European sectors with high reliance on Rust-based cryptography, including finance, telecommunications, and government digital services, could face targeted attacks leveraging this flaw.

CWE-347Improper Verification of Cryptographic Signature (opens in a new tab)
Base weaknessOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
Padding Oracle Crypto Attack (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Feb 2026, 09:28 UTC

WeaknessesCWE-347

Technical details

References

Community reviews

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