CVE-2026-12866

EUVD-2026-38415

23.06.2026, 05:17

All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API. An attacker can execute arbitrary JavaScript by supplying crafted expressions that are compiled into native code using new Function(). Because user-controlled expressions are transformed directly into executable JavaScript, attackers can escape the intended expression sandbox and run arbitrary code within the application's context.

Code Injection

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	9.8 CRITICAL	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: 36%

Common Weakness Enumeration

CWE-94 - Improper Control of Generation of Code ('Code Injection')
The software constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

References

https://github.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55

https://github.com/silentmatt/expr-eval/issues/292

https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690