A critical prototype pollution vulnerability exists in the set-in npm package, specifically in versions 2.0.1 through 2.0.4. This vulnerability allows attackers to manipulate the Object.prototype via crafted input, despite previous attempts to mitigate such risks. Organizations utilizing this package are at significant risk, particularly given the high CVSS score of 9.4, indicating the severity of potential exploitation.
Risk to organizations includes unauthorized manipulation of object properties, which can lead to further security vulnerabilities. This vulnerability's exploitability is classified as critical, highlighting an urgent need for organizations to address it swiftly. The security community has emphasized the importance of updating to version 2.0.5 of the set-in package, which resolves the issue.
The vulnerability was disclosed on February 11, 2026, and the corresponding fix was released shortly thereafter. Organizations leveraging set-in for their applications must ensure they upgrade to mitigate any potential exploitation risks. Failing to address this vulnerability could result in severe consequences for application integrity and user data security.
Organizations should prioritize patching immediately to protect against potential exploitation of this vulnerability.
Vulnerability Details
The set-in project allows for manipulation of nested associative structures through an array of keys. The described prototype pollution vulnerability permits attackers to pollute Object.prototype, which could lead to severe security implications. The issue exists in versions 2.0.1 to 2.0.4, and has been addressed in version 2.0.5.
The CVSS score for this vulnerability is 9.4, classified as critical, indicating the high severity and potential impact. The attack vector is local, with low complexity and no privileges or user interaction required. The vulnerability impacts confidentiality, integrity, and availability, making it essential for organizations to act swiftly.
The CWE classification for this vulnerability is CWE-1321, specifically related to prototype pollution.
Technical Analysis
The root cause of this vulnerability lies in the insufficient validation of user input when attempting to mitigate prototype pollution. The attack vector is local, meaning that an attacker must have access to the environment where the set-in package is utilized. The attack complexity is low, as no special privileges or user interaction is necessary to exploit this vulnerability.
The impacts on confidentiality, integrity, and availability are classified as high, indicating that exploitation of this vulnerability could lead to significant breaches in data security and application functionality.
Risk & Impact Analysis
Organizations utilizing the set-in npm package need to assess the risk associated with this vulnerability. The potential blast radius includes any applications relying on set-in, which could face unauthorized changes to object properties, leading to unpredictable behavior or data loss.
The urgency for remediation is underscored by the vulnerability's CVSS score and the potential for exploitation. Given that it is not currently listed as actively exploited, organizations still face substantial risks if they do not prioritize patching.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the set-in npm package range from 2.0.1 to 2.0.4. Users are advised to upgrade to version 2.0.5 to mitigate the risks associated with this vulnerability.
Mitigation & Remediation
Organizations should patch their applications by upgrading the set-in package to version 2.0.5. If an immediate upgrade is unfeasible, consider implementing input validation to sanitize user inputs and restrict the use of Array.prototype to minimize exposure.
For ongoing security, organizations should review their dependency management processes and ensure regular updates to third-party packages. Additionally, conducting regular security assessments can help identify and remediate similar vulnerabilities in the future.
Organizations should validate remediation through penetration testing to identify similar weaknesses.
Detection Guidance
Monitoring for unusual behavior in applications using the set-in package is essential. Key indicators include unexpected changes in object properties and potential security alerts triggered by input validation failures.
AppSecure Threat Intelligence Insight
The emergence of vulnerabilities like CVE-2026-26021 highlights the ongoing challenges in dependency management within software development. Organizations should adopt a proactive stance towards vulnerability management, including regular updates and comprehensive security assessments, as part of their development lifecycle.
To enhance security posture, consider implementing a robust vulnerability management program and leveraging automated tools for continuous monitoring.
For organizations utilizing cloud services, integrating a cloud penetration testing strategy can further assist in identifying security gaps.
Additionally, understanding the implications of software design choices can provide insights into potential vulnerabilities, helping teams to mitigate risks before they manifest in production.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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