GHSA-7cg8-pq9v-x98q — realms-shim
CRITICALGHSA-7cg8-pq9v-x98q is a critical-severity (CVSS 9.8) vulnerability in realms-shim. A fix is available for realms-shim — see the affected versions and patch details below.
Sandbox Breakout in realms-shim
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
realms-shimnpmDescription
Versions of realms-shim prior to 1.2.1 are vulnerable to a Sandbox Breakout. The Realms evaluation function has an option to apply Babel-like transformations to the source code before it reaches the evaluator. One portion of this transform pipeline exposed a primal-Realm object to the rewriting function. Confined code which used the evaluator itself could provide a malicious rewriter function that captured this object, and use it to breach the sandbox.
Recommendation
Upgrade to version 1.2.1 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | realms-shim | all versions | 1.2.1npm install realms-shim@1.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for realms-shim, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update realms-shim to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7cg8-pq9v-x98q 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-7cg8-pq9v-x98q can be triaged on real exposure rather than presence alone.
Tailored to GHSA-7cg8-pq9v-x98q. 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-7cg8-pq9v-x98q in your dependencies?
O3 Security finds GHSA-7cg8-pq9v-x98q across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.