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TI-2026-66435 Aliases GHSA-cp57-fq8g-qh6v

libcrux has an Incorrect Check of Signer Response Norm During Verification

Priority LOW 38CWE-347Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
Security bypass
Confidentiality · integrity · availability
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Fix status
Fixed

No CVSS vector from any source. Fix status from GitHub. Impact type from CWE-347.

Summary

The ML-DSA verification algorithm as specified in [FIPS 204, subsection 6.3](https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.204.pdf#subsection.6.3) requires verifiers to check that the infinity norm of the deserialized signer response $z$ does not exceed $\gamma_1 - \beta$ (line 13 of Algorithm 8). The same check is required to be performed during signature generation. libcrux-ml-dsa did not perform this check correctly during signature verification, accepting signatures with signer response norm above the allowed maximum value. The check is correctly performed during signing. ## Impact Applications using libcrux-ml-dsa for signature verification would have accepted signatures that would be rejected by a conforming implementation. ## Mitigation Starting from version `0.0.8`, signature verification uses the correct value for $\gamma_1$ in the signer response norm check.

Why it matters now

Fix Fixed libcrux-ml-dsa (crates.io): 0.0.8

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—libcrux-ml-dsa (crates.io)before 0.0.80.0.8Patch availableGHSA-cp57-fq8g-qh6v
  • libcrux-ml-dsa (crates.io) Vendor— Affected before 0.0.8 Fixed in 0.0.8 Patch available GHSA-cp57-fq8g-qh6v

Remediation

  • Fix · GHSA-cp57-fq8g-qh6v libcrux-ml-dsa (crates.io) Fixed in 0.0.8 Advisory →

Timeline

  1. 2026-10-03 Threatist record created from GHSA-cp57-fq8g-qh6v

References

Sources

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