GHSA-2gxj-qrp2-53jv — mopa
CRITICALGHSA-2gxj-qrp2-53jv is a critical-severity (CVSS 9.8) remote code execution vulnerability in mopa. No vendor fix is recorded yet; mitigation options are listed below.
Incorrect reliance on Trait memory layout in mopa
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.
How urgent is this, really
GHSA-2gxj-qrp2-53jv plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
mopaReal-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
The mopa crate redefines the deprecated TraitObject struct from core::raw. This is done to then transmute a reference to a trait object (&dyn Trait for any trait Trait) into this struct and retrieve the data field for the purpose of downcasting. This is used to implement downcast_ref_unchecked(), in terms of which downcast_ref() is also implemented. Same goes for mutable reference downcasting and Box downcasting.
The Rust compiler explicitly reserves the right to change the memory layout of &dyn Trait for any trait Trait. The worst case scenario is that it swaps data and vtable, making an executable location breach and compromisation of ASLR possible, since reads from data would read vtable instead. Likewise, arbitrary code execution is also theoretically possible if reads of vtable generated by the compiler read data instead.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | mopa | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mopa, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of mopa has shipped for GHSA-2gxj-qrp2-53jv yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2gxj-qrp2-53jv can be triaged on real exposure rather than presence alone.
Tailored to GHSA-2gxj-qrp2-53jv. 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-2gxj-qrp2-53jv in your dependencies?
O3 Security finds GHSA-2gxj-qrp2-53jv across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.