Prototype Pollution in cleverbrush Deep Library

The cleverbrush framework and the 'deep' library (versions up to 4.4.0) contain a vulnerability, identified as CVE-2026-78654, originating from the deepExtend function located in 'libs/deep/src/deepExtend.ts'. This flaw allows an attacker to perform prototype pollution, a technique where an attacker manipulates the prototype of base objects. By injecting malicious properties into the object prototype, an attacker can influence the behavior of the application globally. This vulnerability is remotely exploitable and proof-of-concept code has been disclosed, increasing the risk of exploitation. Defenders should prioritize upgrading to version 4.4.1 to remediate this vulnerability, as this patch (810398c1308c500c3b8b6af380b5a89371389327) resolves the improper modification of object attributes.

Impact

Successful exploitation of this prototype pollution vulnerability can lead to unauthorized modification of application state, denial of service, or, in complex scenarios, remote code execution. Because this library is likely used across various web application components, the impact ranges from application-level bypasses to full system compromise depending on how the downstream application utilizes the affected prototype objects.

Recommendation

• Identify all instances of the cleverbrush 'deep' library within the development environment and package lock files.
• Update all dependencies to version 4.4.1 or higher immediately to apply the patch referenced in commit 810398c1308c500c3b8b6af380b5a89371389327.
• Perform a code audit on applications utilizing the 'deepExtend' function to identify if user-controlled input is passed directly to the function without validation.