critical9.8
CVE-2026-12866
All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | expr-eval | <= 2.0.2 | none recorded |
| maven | org.webjars.npm:expr-eval | <= 2.0.2 | none recorded |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-q9v2-7m5w-4693
- https://nvd.nist.gov/vuln/detail/CVE-2026-12866
- https://github.com/silentmatt/expr-eval/issues/292
- https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-17662018
- https://github.com/silentmatt/expr-eval/blob/master/src/expression.js#L55
- https://github.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55