Code injection in expr-eval
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Deferred Red Hat: fix deferred
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-94.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | expr-eval | all versions | — | No fix listed | CNA |
| — | org.webjars.npm:expr-eval | all versions | — | No fix listed | CNA |
| — | expr-eval (npm) | up to 2.0.2 | — | No fix listed | GHSA-q9v2-7m5w-4693 |
| — | org.webjars.npm:expr-eval (Maven) | up to 2.0.2 | — | No fix listed | GHSA-q9v2-7m5w-4693 |
- expr-eval Vendor— Affected all versions Fixed in — No fix listed CNA
- org.webjars.npm:expr-eval Vendor— Affected all versions Fixed in — No fix listed CNA
- expr-eval (npm) Vendor— Affected up to 2.0.2 Fixed in — No fix listed GHSA-q9v2-7m5w-4693
- org.webjars.npm:expr-eval (Maven) Vendor— Affected up to 2.0.2 Fixed in — No fix listed GHSA-q9v2-7m5w-4693
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-12866
- 2026-10-03 Alias added: GHSA-q9v2-7m5w-4693
References
Sources
- CVE-2026-12866 · CVE Program
- CVE-2026-12866 · NVD
- FIRST EPSS
- GHSA-q9v2-7m5w-4693 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-12866 · Red Hat security data · CC BY 4.0
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