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CVE-2026-12866

Published: Jun 23, 2026Updated: Jun 23, 2026 Sources: CVE List NVDCWE-94
NVD MITRE
9.8CVSSCRITICAL
EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-94

Affected Products

expr-evaln/a

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Execution
Initial Access
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References

https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690
security.snyk.io
https://github.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55
github.com
https://github.com/silentmatt/expr-eval/issues/292
github.com

Timeline

Published
Jun 23, 2026
Last Updated
Jun 23, 2026

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