GHSA-mmc9-pwm7-qj5w
CRITICALUnaligned memory access in rand_core
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
rand_core🦀rand_coreReal-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
Impact
Affected versions of this crate violated alignment when casting byte slices to integer slices, resulting in undefined behavior. rand_core::BlockRng::next_u64 and rand_core::BlockRng::fill_bytes are affected.
Patches
The flaw was corrected by Ralf Jung and Diggory Hardy for rand_core >= 0.4.2.
Workarounds
None.
References
See Rand's changelog.
For more information
If you have any questions or comments about this advisory, open an issue in the Rand repository.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | rand_core | ≥ 0.4.0&&< 0.4.2 | 0.4.2 |
| 🦀crates.io | rand_core | all versions | 0.3.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rand_core. 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 rand_core to 0.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mmc9-pwm7-qj5w 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-mmc9-pwm7-qj5w 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-mmc9-pwm7-qj5w. 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-mmc9-pwm7-qj5w in your dependencies?
O3 detects GHSA-mmc9-pwm7-qj5w 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.