CVE-2026-44267
Elo: Sandbox escape to arbitrary Node.js / browser code execution via unfiltered `.constructor` member access in Elo JavaScript emitter
Elo is a purely functional expression language for no-code tools. Prior to 1.0.1, plain Elo strings supplied to defaultFormats.elo.parse(), bin/elo, or elo-lang.org/try can use .constructor.constructor to reach JavaScript Function because the member_access handler in src/transform.ts does not reject meta-properties, src/compilers/javascript.ts emits the surviving property directly, and src/parser.ts accepts constructor as an ordinary identifier. The resulting generated JavaScript executes attacker-selected code in the host runtime. This permits browser script execution and session compromise on the auto-running playground and arbitrary Node.js code execution on library, CI, or DevOps hosts. This plain-string path is distinct from the programmatic AST-object injection issue. This issue is fixed in version 1.0.1.
Fixes and workarounds
Fix
@enspirit/elo (npm): OSV reports a fixed version 1.0.1. Check the advisory for supported release branches.
Source: OSV GHSA-33r5-xmm8-v6x5Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| elo enspirit |
< 1.0.1 (affected) | CNA: GitHub_M |
@enspirit/elo@enspirit/elo
npm |
≥ 0; < 1.0.1 (affected, semver); OSV events: introduced 0; fixed 1.0.1Source events (semver)Other versions: unaffected |
OSV GHSA-33r5-xmm8-v6x5 |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 9.8 critical |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/enspirit/elo/security/advisories/GHSA-33r5-xmm8-v6x5CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/enspirit/elo/commit/2136da1f64eec8ebf99890d3100be9394534b842CNA: GitHub_M · x_refsource_MISC
- https://github.com/enspirit/elo/commit/d2a89a8db76a244eb740687524a7e8529b7554b5CNA: GitHub_M · x_refsource_MISC
- https://github.com/advisories/GHSA-33r5-xmm8-v6x5OSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-33r5-xmm8-v6x5OSV / GitHub Security Advisories · osv
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