CVE-2026-12209 Details
Description
A security vulnerability has been detected in RubyLouvre avalon up to 2.2.10. The impacted element is an unknown function of the file src/filters/index.js of the component Template Filter Handler. Such manipulation leads to improperly controlled modification of object prototype attributes. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
A vulnerability allowing prototype escaping and remote code execution has been identified in RubyLouvre Avalon versions through 2.2.10. The issue arises from the Template Filter Handler, specifically in the file 'src/filters/index.js'. The vulnerability is rooted in the improper handling of template filters, which are stored in a plain object and accessed without a 'hasOwnProperty' check. This oversight enables traversal of the prototype chain, allowing access to 'Object.prototype' properties. Exploitation is possible by injecting controlled template content, which can be executed as JavaScript code via 'new Function()'.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jun 15, 2026CISA-ADP
Assessed Jun 15, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/OriginSecurityX/avalon-filter-rce | [email protected] | ExploitTechnical Description |
| https://vuldb.com/cve/CVE-2026-12209 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/submit/832447 | [email protected] | Issue TrackingPermission Required |
| https://vuldb.com/vuln/370851 | [email protected] | BundlePermission Required |
| https://vuldb.com/vuln/370851/cti | [email protected] | Content Wall |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-1321 | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') | [email protected] |
| CWE-94 | Improper Control of Generation of Code ('Code Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| RubyLouvre avalon | >= 0.9.9, <= 2.2.10 (semver) |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 15, 2026 | New CVE Received | [email protected] |