CVE-2026-24850
CVE-2026-24850 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. 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-347.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- EPSS exploit prediction: 0% (22nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-4910
- Weakness: CWE-347
- Published:
- Last modified:
Description
The ML-DSA crate is a Rust implementation of the Module-Lattice-Based Digital Signature Standard (ML-DSA). Starting in version 0.0.4 and prior to version 0.1.0-rc.4, the ML-DSA signature verification implementation in the RustCrypto `ml-dsa` crate incorrectly accepts signatures with repeated (duplicate) hint indices. According to the ML-DSA specification (FIPS 204 / RFC 9881), hint indices within each polynomial must be **strictly increasing**. The current implementation uses a non-strict monotonic check (`<=` instead of `<`), allowing duplicate indices. This is a regression bug. The original implementation was correct, but a commit in version 0.0.4 inadvertently changed the strict `<` comparison to `<=`, introducing the vulnerability. Version 0.1.0-rc.4 fixes the issue.
Frequently asked questions
- What is CVE-2026-24850?
- The ML-DSA crate is a Rust implementation of the Module-Lattice-Based Digital Signature Standard (ML-DSA). Starting in version 0.0.4 and prior to version 0.1.0-rc.4, the ML-DSA signature verification implementation in the RustCrypto `ml-dsa` crate incorrectly accepts signatures with repeated (duplicate) hint indices. According to the ML-DSA specification (FIPS 204 / RFC 9881), hint indices within each polynomial must be **strictly increasing**. The current implementation uses a non-strict monotonic check (`<=` instead of `<`), allowing duplicate indices. This is a regression bug. The original implementation was correct, but a commit in version 0.0.4 inadvertently changed the strict `<` comparison to `<=`, introducing the vulnerability. Version 0.1.0-rc.4 fixes the issue.
- How severe is CVE-2026-24850?
- CVE-2026-24850 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2026-24850 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-24850?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-24850 have an EU (EUVD) identifier?
- Yes. CVE-2026-24850 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4910.
- When was CVE-2026-24850 published?
- CVE-2026-24850 was published on 2026-01-28 and last updated on 2026-06-17.
References
- https://csrc.nist.gov/pubs/fips/204/final
- https://datatracker.ietf.org/doc/html/rfc9881
- https://github.com/C2SP/wycheproof
- https://github.com/C2SP/wycheproof/blob/master/testvectors_v1/mldsa_44_verify_test.json
- https://github.com/C2SP/wycheproof/blob/master/testvectors_v1/mldsa_65_verify_test.json
- https://github.com/C2SP/wycheproof/blob/master/testvectors_v1/mldsa_87_verify_test.json
- https://github.com/RustCrypto/signatures/commit/400961412be2e2ab787942cf30e0a9b66b37a54a
- https://github.com/RustCrypto/signatures/commit/b01c3b73dd08d0094e089aa234f78b6089ec1f38
- https://github.com/RustCrypto/signatures/issues/894
- https://github.com/RustCrypto/signatures/pull/895
- https://github.com/RustCrypto/signatures/security/advisories/GHSA-5x2r-hc65-25f9
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