Vulnerability · Published Jun 15, 2026 · Assigned by VulDB
CVE-2026-12209RubyLouvre avalon Template Filter index.js prototype pollution
Medium 5.3
In plain English
A medium-severity prototype pollution in avalon from RubyLouvre. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RubyLouvre | avalon | 2.2.02.2.12.2.22.2.32.2.42.2.52.2.62.2.7 |
Weakness: CWE-1321, CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
References
- VDB-370851 | RubyLouvre avalon Template Filter index.js prototype pollution vdb-entry
- VDB-370851 | CTI Indicators (IOB, IOC, TTP, IOA) signature, permissions-required
- CVE-2026-12209 | CVE Analysis and Report third-party-advisory
- Submit #832447 | RubyLouvre avalon 0.9.9 - 2.2.10 Code Injection / Prototype Pollution third-party-advisory
- https://github.com/OriginSecurityX/avalon-filter-rce exploit