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RUSTSEC-2026-0076

Panic in Signature Hint Decoding During Verification

Reported
Issued
Package
libcrux-ml-dsa (crates.io)
Type
Vulnerability
References
CVSS Score
8.7 HIGH
CVSS Details
Attack Complexity
Low
Attack Requirements
None
Attack Vector
Network
Privileges Required
None
Availability Impact to the Subsequent System
None
Confidentiality Impact to the Subsequent System
None
Integrity Impact to the Subsequent System
None
User Interaction
None
Availability Impact to the Vulnerable System
High
Confidentiality Impact to the Vulnerable System
None
Integrity Impact to the Vulnerable System
None
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Patched
  • >=0.0.8
Affected Functions
Version
libcrux_ml_dsa::ml_dsa_44::verify
  • <=0.0.7
libcrux_ml_dsa::ml_dsa_65::verify
  • <=0.0.7
libcrux_ml_dsa::ml_dsa_87::verify
  • <=0.0.7

Description

During ML-DSA verification the serialized hint values are decoded as specified in algorithm 22 HintBitUnpack of FIPS 204, subsection 7.1. The algorithm requires that the cumulative hint counters per row of the hint vector are strictly increasing and below a maximum value which depends on the choice of ML-DSA parameter set (line 4).

In libcrux-ml-dsa, hint decoding did not check the boundedness of the cumulative hint counter of the last row of the hint vector.

Impact

A manipulated invalid hint can cause an out-of-bounds memory access since the hint decoding logic may attempt to read outside the bounds of the serialized signature, causing a runtime panic.

Mitigation

Starting from version 0.0.8, hint decoding will check the cumulative hint counter of the last row as well.

Advisory available under CC0-1.0 license.