Summary
Mimalloc Can Allocate Memory with Bad Alignment
This crate depended on a promise regarding alignments made by the author of the mimalloc allocator to avoid using aligned allocation functions where possible for performance reasons.
Since then, the mimalloc allocator's logic changed, making it break this promise.
This caused this crate to return memory with an incorrect alignment for some allocations, particularly those with large alignments.
The flaw was fixed by always using the aligned allocation functions.
Impact
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.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-G23H-7VF9-XC25? GHSA-G23H-7VF9-XC25 is a medium-severity security vulnerability in mimalloc (rust), affecting versions < 0.1.39. It is fixed in 0.1.39.
- Which versions of mimalloc are affected by GHSA-G23H-7VF9-XC25? mimalloc (rust) versions < 0.1.39 is affected.
- Is there a fix for GHSA-G23H-7VF9-XC25? Yes. GHSA-G23H-7VF9-XC25 is fixed in 0.1.39. Upgrade to this version or later.
- Is GHSA-G23H-7VF9-XC25 exploitable, and should I be worried? Whether GHSA-G23H-7VF9-XC25 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-G23H-7VF9-XC25 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-G23H-7VF9-XC25? Upgrade
mimallocto 0.1.39 or later.