What’s Vulnerable › Vulnerabilities

CVE-2026-12866

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-23 · updated 2026-07-07
• Weakness: CWE-94

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.

Affected products

• expr-eval: all versions
• org.webjars.npm:expr-eval: all versions

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

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