Sandbox Breakout in realms-shim
Priority LOW 38Published · Updated
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from GitHub.
Summary
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.
Why it matters now
Fix Fixed realms-shim (npm): 1.2.1
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | realms-shim (npm) | before 1.2.1 | 1.2.1 | Patch available | GHSA-7cg8-pq9v-x98q |
- realms-shim (npm) Vendor— Affected before 1.2.1 Fixed in 1.2.1 Patch available GHSA-7cg8-pq9v-x98q
Remediation
- Fix · GHSA-7cg8-pq9v-x98q realms-shim (npm) Fixed in 1.2.1 Advisory →
Timeline
- 2026-10-03 Threatist record created from GHSA-7cg8-pq9v-x98q
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences