RubyLouvre avalon up to 2.2.10 Template Filter src/filters/index.js prototype pollution

Summaryinfo

A vulnerability was found in RubyLouvre avalon up to 2.2.10. It has been classified as critical. This affects an unknown function of the file src/filters/index.js of the component Template Filter Handler. Performing a manipulation results in prototype pollution. This vulnerability is identified as CVE-2026-12209. The attack can be initiated remotely. Additionally, an exploit exists. The vendor was contacted early about this disclosure but did not respond in any way.

Detailsinfo

A vulnerability was found in RubyLouvre avalon up to 2.2.10. It has been classified as critical. This affects an unknown code block of the file src/filters/index.js of the component Template Filter Handler. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. This is going to have an impact on integrity.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-12209. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details and a public exploit are known. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

The exploit is shared for download at github.com. It is declared as proof-of-concept. The vendor was contacted early about this disclosure but did not respond in any way.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36683). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Programming Language Software

Vendor

• RubyLouvre

Name

• avalon

Version

• 2.2.0
• 2.2.1
• 2.2.2
• 2.2.3
• 2.2.4
• 2.2.5
• 2.2.6
• 2.2.7
• 2.2.8
• 2.2.9
• 2.2.10

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Submitinfo

Accepted

• Submit #832447: RubyLouvre avalon 0.9.9 - 2.2.10 Code Injection / Prototype Pollution (by Frederick)

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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