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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.

PUBLISHED Reserved 2026-06-22 | Published 2026-06-23 | Updated 2026-06-27 | Assigner snyk




CRITICAL: 9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CRITICAL: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Problem types

Code Execution

Credits

Dinh Twan Doan

References

security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690 exploit

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

github.com/...tt/expr-eval/blob/master/src/expression.js#L55

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

cve.org (CVE-2026-12866)

nvd.nist.gov (CVE-2026-12866)

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