CVE-2026-86186 in AVideo
Summary
by MITRE • 09/05/2026
AVideo API fails to enforce rate limits when clients send a bot User-Agent header, allowing attackers to bypass all eight protected operations including login brute-force protection. Attackers can send requests with a bot User-Agent to disable rate limiting and perform unlimited password guessing attempts against any account from a single IP address.
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Analysis
by VulDB Data Team • 09/05/2026
The vulnerability in AVideo API represents a critical authentication security flaw rooted in improper access control mechanisms, specifically the failure to enforce rate limiting policies under specific header conditions. This issue is categorized under CWE-307 Improper Restriction of Excessive Authentication Attempts and aligns with MITRE ATT&CK technique T1110 Brute Force. The core technical deficiency lies in the application logic that governs request throttling, which contains a conditional bypass triggered by the presence of a bot User-Agent header. Instead of applying uniform security controls to all incoming requests regardless of their claimed identity, the system selectively disables protective measures for traffic identified as automated or bot-driven. This design oversight allows malicious actors to circumvent safeguards intended to mitigate credential stuffing and brute-force attacks, effectively rendering these defenses obsolete against targeted assaults originating from a single source IP address.
From an operational perspective, this vulnerability enables attackers to perform unlimited password guessing attempts without triggering account lockouts or receiving HTTP 429 Too Many Requests responses that would normally indicate rate limit exhaustion. By spoofing the User-Agent header to mimic legitimate bot traffic, adversaries can systematically test large volumes of credentials against user accounts with minimal risk of detection or interruption. This capability significantly lowers the barrier for unauthorized access, as attackers are no longer constrained by temporal delays between attempts. The impact extends beyond simple account compromise; it facilitates broader reconnaissance and potential data exfiltration if weak passwords are discovered. Furthermore, because the bypass applies to all eight protected operations within the API, the scope of exploitation is broad, affecting not only login endpoints but potentially other authenticated actions that rely on similar rate-limiting logic for abuse prevention.
The security implications are severe, as this flaw undermines the fundamental principle of defense in depth by removing a key layer of protection against automated attacks. Attackers can leverage tools like Hydra or custom scripts to rapidly iterate through password dictionaries, increasing the probability of success significantly compared to scenarios where rate limiting is enforced. This vulnerability also poses a risk to system integrity and availability, as successful brute-force attempts may lead to privilege escalation if administrative accounts are targeted. Additionally, the ability to bypass these controls can be used for denial-of-service purposes by generating excessive authenticated traffic that consumes server resources without being throttled.
To mitigate this vulnerability, immediate remediation should focus on correcting the access control logic within the AVideo API codebase. Developers must ensure that rate limiting is applied consistently across all client types and headers, removing any conditional exemptions based on User-Agent strings. Implementing a whitelist approach for trusted bot traffic or applying stricter validation criteria can help distinguish between legitimate automation and malicious activity without compromising security controls. It is also recommended to integrate multi-factor authentication (MFA) as an additional layer of defense that remains effective even if rate limiting is bypassed. Furthermore, organizations should deploy Web Application Firewalls configured with rules to detect and block anomalous login patterns regardless of header values, ensuring that brute-force attempts are identified and mitigated at the network perimeter level. Regular security audits and penetration testing focused on authentication flows can help identify similar logic flaws in other parts of the application architecture.