CVE-2026-90481 in Burp Suite DAST
Summary
by MITRE • 09/24/2026
In PortSwigger Burp Suite DAST (formerly Burp Suite Enterprise Edition) before 2026.8, an authentication bypass can occur via an alternate path or channel.
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Analysis
by VulDB Data Team • 09/24/2026
The vulnerability identified in versions of PortSwigger Burp Suite DAST prior to the 2026.8 release represents a critical security flaw centered on improper access control mechanisms within the application's architecture. This specific issue allows for authentication bypass through an alternate path or channel, indicating that while certain entry points may be properly secured with robust authentication checks, other endpoints or API routes remain inadequately protected. In complex web applications and dynamic analysis tools like Burp Suite DAST, it is common to have multiple interfaces for interaction, including graphical user interface components, RESTful APIs, WebSocket connections, and internal service-to-service communication channels. When developers secure one path but neglect others, attackers can exploit these discrepancies to gain unauthorized access without valid credentials. This type of flaw is fundamentally rooted in a failure to enforce consistent security policies across all available entry points within the system boundary.
From a technical perspective, this vulnerability aligns closely with CWE-287, which describes Improper Authentication, and more specifically CWE-345, Insufficient Verification of Data Authenticity when considering how alternate channels might bypass standard validation routines. The attack vector likely involves identifying an undocumented or less scrutinized endpoint that performs sensitive operations such as retrieving scan results, modifying configurations, or accessing user data without requiring a valid session token or multi-factor authentication proof. By leveraging this alternative channel, an attacker can circumvent the primary login mechanism entirely. This is particularly dangerous in enterprise environments where Burp Suite DAST is used to continuously monitor and assess other applications for vulnerabilities; compromising the scanner itself provides attackers with deep insights into the security posture of their targets, including discovered weaknesses, scan configurations, and potentially sensitive data processed during assessments.
The operational impact of this authentication bypass is severe, as it undermines the integrity and confidentiality guarantees provided by the software. An authenticated attacker could manipulate ongoing vulnerability scans to hide malicious activities or false positives, thereby misleading security teams into believing a system is secure when it is not. Furthermore, access to scan results may reveal critical vulnerabilities in client infrastructure that were previously unknown, effectively handing over a roadmap of exploitable weaknesses to adversaries. In the context of the MITRE ATT&CK framework, this behavior maps directly to T1078 Valid Accounts and potentially T1528 Steal Application Access Token if session tokens are harvested via the alternate channel. The ability to bypass authentication allows for unauthorized modification of scan targets, which could be used to direct scans against critical production systems without authorization, leading to potential service disruption or data exfiltration through side channels created by aggressive scanning techniques.
Mitigation strategies must focus on implementing a defense-in-depth approach that ensures all communication paths are subject to the same rigorous authentication and authorization checks. Developers should conduct a comprehensive audit of all API endpoints and internal services within Burp Suite DAST to verify that no alternate routes exist for sensitive operations without proper validation. Implementing centralized access control middleware can help enforce consistent policies across different channels, ensuring that every request is authenticated regardless of its entry point. Additionally, enabling detailed logging and monitoring for authentication failures on non-standard paths can aid in early detection of such bypass attempts. For users currently running affected versions, upgrading to version 2026.8 or later is the primary remediation step provided by PortSwigger. Until an upgrade is feasible, network-level controls such as strict firewall rules limiting access to administrative interfaces and IP whitelisting can provide a temporary layer of protection against unauthorized exploitation of these alternate channels.