CVE-2026-77145 in Events 2
Summary
by MITRE • 08/25/2026
The permission check for the frontend management update flow verified a different event than the one the request went on to modify. A user with frontend event management access could therefore modify events belonging to other organizers.
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Analysis
by VulDB Data Team • 08/25/2026
This vulnerability represents a critical failure in server-side authorization logic, specifically categorized under CWE-284 Improper Access Control and often associated with Broken Function Level Authorization within the OWASP Top 10 framework. The core technical flaw lies in a mismatch between the security check performed by the application backend and the actual resource targeted for modification during the frontend event management update flow. In secure architectural designs, authorization checks must be tightly coupled to the specific identifier of the resource being accessed or modified at the moment of execution. However, in this instance, the system validated permissions against one event object while simultaneously applying changes to a different event object identified by separate input parameters. This decoupling creates an opportunity for unauthorized actors to bypass access restrictions entirely.
The operational impact of this flaw is severe, allowing any user with basic frontend event management privileges to escalate their effective rights and modify events belonging to other organizers. Since the permission check was satisfied based on a different context than the one being altered, the application failed to enforce isolation between distinct organizational entities or individual users' data sets. This leads directly to CWE-602 Client-Side Enforcement of Server-Side Access Control if the frontend logic relied on client-side signals that were spoofed, but more accurately reflects CWE-862 Missing Authorization Check for the specific target resource. An attacker can manipulate request parameters such as event IDs or internal identifiers to point toward resources they do not own while retaining valid credentials and session tokens associated with a different, authorized event. This results in unauthorized data modification, potential integrity loss of critical scheduling information, and exposure of sensitive organizational details that were intended to remain private to other organizers.
From an offensive security perspective, this vulnerability aligns with the MITRE ATT&CK technique T1078 Valid Accounts, as it leverages legitimate credentials to perform actions outside their intended scope, specifically falling under lateral movement or privilege escalation contexts depending on the severity of data accessed. The ability to alter events for other organizers can disrupt business operations, cause financial loss through cancelled bookings or incorrect scheduling, and damage organizational reputation due to public-facing errors introduced by malicious insiders or compromised accounts.
Mitigation requires a rigorous review of all authorization logic within the application backend. Developers must ensure that every state-changing operation performs an explicit access control check against the exact resource identifier provided in the request payload. This involves validating that the authenticated user owns, manages, or has explicit permission to modify the specific event instance targeted by the update action. Implementing robust server-side validation is essential, as client-side checks are trivially bypassable. Additionally, adopting a principle of least privilege and ensuring that session contexts do not carry ambiguous state regarding which resource is currently being acted upon will further reduce risk. Regular security testing using dynamic application security scanning tools configured to detect authorization flaws can help identify similar patterns in other parts of the system before they are exploited in production environments.