CVE-2026-12866

CRITICAL 9.8

CVSS Score

9.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-94
Vendor	n/a
Product	expr-eval
Published	Jun 23, 2026

Stay Ahead of the Next One

Get instant alerts for n/a expr-eval

Be the first to know when new critical vulnerabilities affecting n/a expr-eval are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

n/a / expr-eval

0 < *

References

NVD ↗ CVE.org ↗ EPSS Data ↗

security.snyk.io: https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690 github.com: https://github.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55 github.com: https://github.com/silentmatt/expr-eval/issues/292

Credits

Dinh Twan Doan