agoric/realms-shim · Security
Sandbox Breakout in realms-shim
- GHSA ID
- GHSA-7cg8-pq9v-x98q
- Severity
- critical
- Published
- Updated
- CVSS
- 9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS v3
- 9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description
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.