CVE-2026-12866

critical · 9.2

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.

9.2

CVSS

0.9%

EPSS (exploit prob.)

57th

EPSS percentile

2026-06-23

Published

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-94

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-JAVA-ORGWEBJARSNPM-17662018
https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690
https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-12866