Summary
libcrux: Panic in Signature Hint Decoding During Verification
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.
Mitigation
Starting from version 0.0.8, hint decoding will check the cumulative hint counter of the last row as well.
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.
A read operation accesses a memory location beyond the intended buffer boundary. Typical impact: sensitive data disclosure or crash.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-XRF2-5R3P-5WGJ? GHSA-XRF2-5R3P-5WGJ is a high-severity out-of-bounds read vulnerability in libcrux-ml-dsa (rust), affecting versions < 0.0.8. It is fixed in 0.0.8. A read operation accesses a memory location beyond the intended buffer boundary.
- Which versions of libcrux-ml-dsa are affected by GHSA-XRF2-5R3P-5WGJ? libcrux-ml-dsa (rust) versions < 0.0.8 is affected.
- Is there a fix for GHSA-XRF2-5R3P-5WGJ? Yes. GHSA-XRF2-5R3P-5WGJ is fixed in 0.0.8. Upgrade to this version or later.
- Is GHSA-XRF2-5R3P-5WGJ exploitable, and should I be worried? Whether GHSA-XRF2-5R3P-5WGJ is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-XRF2-5R3P-5WGJ is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-XRF2-5R3P-5WGJ? Upgrade
libcrux-ml-dsato 0.0.8 or later.