CVE-2026-12866

critical

Description

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.

References

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

https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-17662018

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

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

Details

Source: Mitre, NVD

Published: 2026-06-23

Updated: 2026-07-07

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

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

Severity: Critical

CVSS v4

Base Score: 9.2

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00454