CVE-2026-40910 is a medium-severity vulnerability affecting Fatedier's frp, a fast reverse proxy. This vulnerability allows for an authentication bypass in the HTTP vhost routing path when the routeByHTTPUser feature is employed as part of access control. It exists in versions from 0.43.0 to 0.68.0 and is resolved in version 0.68.1.
The vulnerability arises due to a discrepancy in how the routing logic and access control checks are performed. Specifically, in proxy-style requests, the routing logic utilizes the username from the Proxy-Authorization header to select the appropriate routeByHTTPUser backend, while the access control verification relies on the credentials from the standard Authorization header. Consequently, an attacker who can access the HTTP vhost entrypoint and knows or can guess the protected routeByHTTPUser value may gain access to a backend secured by httpUser / httpPassword, even with an incorrect Proxy-Authorization password.
This issue impacts deployments specifically using the routeByHTTPUser feature and does not affect standard HTTP proxies that do not implement it. Given the potential for unauthorized backend access, organizations utilizing affected versions are advised to prioritize remediation.
The CVSS score of 6.5 indicates a medium severity level for this vulnerability, highlighting the importance of addressing it to mitigate any potential impacts.
Vulnerability Details
The CVE-2026-40910 vulnerability is classified under CWE-287, which pertains to improper authentication. The CVSS score derived from the NVD indicates a critical severity level of 9.1, while the GitHub advisory assigns a medium severity of 6.5 based on different metrics. The varying scores reflect different perspectives on the vulnerability's potential impact.
Technical Analysis
The root cause of CVE-2026-40910 lies in the authentication bypass process due to the misalignment between the Proxy-Authorization and Authorization headers. The attack vector is categorized as network-based, requiring no privileges and no user interaction, making it relatively straightforward for an attacker to exploit.
The attack complexity is marked as high, indicating that while the vulnerability can be exploited, it may require specific conditions or knowledge about the configuration. The potential impacts are classified as having a high confidentiality impact with a low integrity impact and no availability impact.
Risk & Impact Analysis
Risk to organizations includes the potential for unauthorized access to sensitive backend systems, which can lead to data breaches or other security incidents. The impact is particularly significant for organizations that rely on frp for critical network functions, as attackers may exploit this vulnerability to gain access to protected resources.
Given the CVSS base score of 6.5 and the fact that the vulnerability is not included in the KEV catalog, organizations should address this vulnerability in their patch management processes, emphasizing its importance in the context of their overall security posture.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects Fatedier's frp in versions from 0.43.0 to 0.68.0. Organizations running these versions should upgrade to 0.68.1 or later to mitigate the risk associated with this vulnerability.
Mitigation & Remediation
Organizations should prioritize upgrading to frp version 0.68.1 or later as a primary remediation step. If an immediate upgrade is not feasible, organizations should implement network controls, such as restricting access to the HTTP vhost entrypoint to trusted sources, to mitigate exposure. Additionally, regular monitoring for any unauthorized access attempts should be conducted to detect potential exploitation attempts.
For further assistance in identifying vulnerabilities and implementing security measures, organizations can consider engaging in penetration testing to validate their security posture.
Detection Guidance
To detect potential exploitation of CVE-2026-40910, organizations should monitor logs for unusual access patterns, specifically looking for unauthorized access attempts that may indicate exploitation attempts. Additionally, behavioral anomalies surrounding the HTTP vhost entrypoint should be analyzed to identify any signs of unauthorized access.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2026-40910 emphasizes the necessity for organizations to maintain robust access controls within their network configurations. This vulnerability highlights the risks associated with misconfigured access controls in modern application architectures.
As attackers evolve their strategies, understanding vulnerabilities like CVE-2026-40910 will be crucial for security teams to enhance their defensive measures. For comprehensive security strategies, organizations are encouraged to review their exposure to vulnerabilities by engaging in vulnerability management programs and consider adopting proactive security measures.
Moreover, the trends revealed through vulnerabilities like this can guide organizations in strengthening their overall security posture. For more insights on current threat landscapes, organizations should stay informed by engaging with ransomware statistics and adapting their defenses accordingly.
Finally, organizations should consider exploring specialized services for enhanced security, such as red teaming services to better understand their security vulnerabilities and improve their resilience against future threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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