Elo: Sandbox escape to arbitrary Node.js / browser code execution via unfiltered `.constructor` member access in Elo JavaScript emitter

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-44267
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-03 18:18:03 UTC
Updated2026-11-03 18:18:03 UTC
DescriptionElo 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-79 | CWE-94 | CWE-693 | CWE-1336 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection') | CWE-693 CWE-693: Protection Mechanism Failure | CWE-1336 CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Enspirit Elo affected < 1.0.1 Not specified

References

ReferenceSourceLinkTags
github.com/enspirit/elo/commit/2136da1f64eec8ebf99890d3100be9394534b842 [email protected] github.com
github.com/enspirit/elo/security/advisories/GHSA-33r5-xmm8-v6x5 [email protected] github.com
github.com/enspirit/elo/commit/d2a89a8db76a244eb740687524a7e8529b7554b5 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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