CVE-2026-0601 in Nexus Repository
Summary
by MITRE • 01/15/2026
A reflected cross-site scripting vulnerability exists in Nexus Repository 3 that allows unauthenticated attackers to execute arbitrary JavaScript in a victim's browser through a specially crafted request requiring user interaction.
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Analysis
by VulDB Data Team • 01/15/2026
The reflected cross-site scripting vulnerability identified as CVE-2026-0601 represents a critical security flaw within Nexus Repository 3 software that exposes organizations to significant web application risks. This vulnerability specifically affects the repository management system's handling of user input parameters, creating an attack vector that can be exploited by unauthenticated threat actors without requiring any prior authentication credentials. The flaw manifests when the application fails to properly sanitize or encode user-supplied data before reflecting it back in HTTP responses, allowing malicious payloads to be executed within the context of a victim's browser session.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding mechanisms within Nexus Repository 3's web interface components. When a user visits a maliciously crafted URL containing XSS payloads, the application processes the request and reflects the malicious input back to the user's browser without adequate sanitization. This particular vulnerability requires user interaction to be effective, meaning that attackers must convince victims to click on malicious links or visit compromised web pages, which aligns with the typical characteristics of phishing attacks or social engineering campaigns. The reflected nature of the vulnerability indicates that the malicious input is immediately reflected in the application's response without being stored, making it a classic example of a server-side XSS flaw that operates through the application's dynamic response generation.
The operational impact of CVE-2026-0601 extends beyond simple script execution, as successful exploitation can lead to complete session hijacking, credential theft, and unauthorized access to repository contents. Attackers can leverage this vulnerability to steal user authentication tokens, modify repository configurations, access sensitive artifacts, or redirect users to malicious domains. The unauthenticated nature of the attack means that organizations cannot rely on traditional authentication-based defenses to protect against this threat, requiring comprehensive application-level protections. This vulnerability particularly affects organizations that rely heavily on Nexus Repository 3 for artifact management, as compromised repositories could result in supply chain attacks, code injection, or unauthorized modification of critical software components. The vulnerability's classification under CWE-79 (Cross-site Scripting) and its alignment with ATT&CK technique T1566.001 (Phishing) demonstrates the multi-faceted nature of the threat landscape it creates.
Organizations should implement immediate mitigations including comprehensive input validation, output encoding, and the implementation of Content Security Policy headers to prevent unauthorized script execution. The recommended approach involves updating to patched versions of Nexus Repository 3, implementing proper request filtering mechanisms, and establishing monitoring for suspicious user interactions. Additionally, organizations should conduct thorough security assessments of their repository environments, implement web application firewalls, and establish incident response procedures specifically addressing XSS vulnerabilities. Regular security training for administrators and developers regarding secure coding practices remains essential to prevent similar vulnerabilities in future deployments. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against persistent web application threats.