Summary
git2 has potential undefined behavior when dereferencing Buf struct
If the Buf struct is dereferenced immediately after calling new() or default() on the Buf struct, a null pointer is passed to the unsafe function slice::from_raw_parts. According to the safety section documentation of the function, data must be non-null and aligned even for zero-length slices or slices of ZSTs. Thus, passing a null pointer will lead to undefined behavior.
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via 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-J39J-6GW9-JW6H? GHSA-J39J-6GW9-JW6H is a low-severity null pointer dereference vulnerability in git2 (rust), affecting versions < 0.20.4. It is fixed in 0.20.4. The application dereferences a null pointer, causing a crash.
- Which versions of git2 are affected by GHSA-J39J-6GW9-JW6H? git2 (rust) versions < 0.20.4 is affected.
- Is there a fix for GHSA-J39J-6GW9-JW6H? Yes. GHSA-J39J-6GW9-JW6H is fixed in 0.20.4. Upgrade to this version or later.
- Is GHSA-J39J-6GW9-JW6H exploitable, and should I be worried? Whether GHSA-J39J-6GW9-JW6H 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-J39J-6GW9-JW6H 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-J39J-6GW9-JW6H? Upgrade
git2to 0.20.4 or later.