Bug 2491633 (CVE-2026-12866)

Summary: CVE-2026-12866 expr-eval: expr-eval: Code Execution via crafted expressions in toJSFunction() API
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: bbrownin
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in expr-eval. A remote attacker can exploit this vulnerability by supplying crafted expressions to the toJSFunction() API. These expressions are then compiled into native code using new Function(), allowing the attacker to execute arbitrary JavaScript code. This can lead to arbitrary code execution within the application's context, potentially compromising the system.
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Description OSIDB Bzimport 2026-06-23 06:01:16 UTC
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.