Platform
nodejs
Component
convict
Fixed in
6.2.5
6.2.5
CVE-2026-33864 represents a prototype pollution vulnerability discovered in the convict npm package. This flaw enables attackers to manipulate the Object.prototype, potentially leading to unpredictable application behavior and security compromises. The vulnerability affects versions 6.2.4 and prior; however, a fix is available in version 6.2.5.
CVE-2026-33864 affects the npm package 'convict', specifically version 6.2.4. This is a prototype pollution vulnerability that allows attackers to modify the behavior of JavaScript objects, even Object.prototype, potentially leading to arbitrary code execution or denial of service. While a previous fix attempted to prevent this, a new exploitation technique using String.prototype has demonstrated that the protection is insufficient. The CVSS severity score is rated 9.5, indicating a critical risk. Prototype pollution can impact any code utilizing JavaScript objects, expanding the attack surface. The vulnerability lies in the configuration handling logic within the package, where user input is not properly validated before being used to update the configuration.
The vulnerability is exploited by crafting a malicious input string that, when processed by 'convict', pollutes the Object.prototype. This pollution allows attackers to inject custom properties into all JavaScript objects, which can be used to alter application behavior. The exploitation technique leverages the capabilities of String.prototype to bypass protections implemented in the previous fix. The attacker needs to have the ability to provide input to the system that is processed by 'convict'. This could be through an API, a configuration file, or any other data input mechanism. The complexity of exploitation is relatively low, as the malicious input string is relatively simple to construct.
The immediate recommended mitigation is to update the 'convict' package to version 6.2.5 or higher. This version includes a fix that addresses the prototype pollution vulnerability. If updating is not immediately possible, consider implementing additional security measures, such as strict validation of user input before using it in 'convict' configuration. Reviewing code that utilizes 'convict' to identify potential vulnerable entry points and applying additional protections is also advised. Monitoring application logs for unusual behavior related to JavaScript object manipulation can help detect and respond to potential attacks. Updating is the most effective and recommended solution.
No official patch available. Check for workarounds or monitor for updates.
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Prototype pollution is a vulnerability that allows attackers to modify the behavior of JavaScript objects by adding or modifying properties on an object's prototype. This can have serious consequences, such as arbitrary code execution.
The vulnerability has a high severity score (CVSS 9.5) because it can allow attackers to compromise the security of the application by modifying the behavior of fundamental JavaScript objects.
If you cannot update immediately, strictly validate user input and review your code for potential vulnerable entry points.
Monitor application logs for unusual behavior related to JavaScript object manipulation.
There are static and dynamic security analysis tools that can help detect prototype pollution vulnerabilities.
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