GHSA-g23h-7vf9-xc25
Mimalloc Can Allocate Memory with Bad Alignment
Blast Radius
mimallocReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | mimalloc | all versions | 0.1.39 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mimalloc. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update mimalloc to 0.1.39 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g23h-7vf9-xc25 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-g23h-7vf9-xc25 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-g23h-7vf9-xc25. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g23h-7vf9-xc25 in your dependencies?
O3 detects GHSA-g23h-7vf9-xc25 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.