CVE-2026-82657 in Admidio
Summary
by MITRE • 08/30/2026
Admidio before 5.0.12 fails to enforce login-only module restrictions in RSS feed endpoints for forum and announcements modules. Unauthenticated attackers can retrieve forum topics and announcements by sending GET requests to rss/forum.php or rss/announcements.php, disclosing titles, full post text, author names, and timestamps.
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Analysis
by VulDB Data Team • 08/30/2026
The vulnerability identified in Admidio versions prior to 5.0.12 represents a critical failure in access control mechanisms within the application's RSS feed generation components. Specifically, the endpoints rss/forum.php and rss/announcements.php are designed to provide syndicated content for forum topics and announcements respectively. However, these modules fail to properly enforce login-only restrictions that apply to their corresponding web interfaces. This architectural oversight allows unauthenticated users to bypass authentication requirements by directly accessing these RSS feed URLs via standard HTTP GET requests. The flaw stems from a lack of session validation or permission checks within the backend logic responsible for rendering the XML data for these feeds, effectively treating public-facing syndication endpoints as accessible without verifying user identity or role-based permissions.
From a technical perspective, this vulnerability is classified under CWE-287, which denotes Improper Authentication, and more specifically aligns with CWE-306, Missing Authentication for Critical Function. The operational impact of this flaw is significant because it results in the disclosure of sensitive information that was intended to be restricted to registered users only. Attackers can retrieve forum topic titles, full post text, author names, and timestamps without any form of authentication. This exposure not only violates user privacy expectations but also provides attackers with valuable intelligence for further social engineering attacks or targeted exploitation attempts. The availability of full post content may reveal internal discussions, personal data shared in forums, or strategic information contained within announcements that were meant to be confidential.
This type of vulnerability is often associated with the ATT&CK technique T1078, Valid Accounts, although in this specific case, it allows access without valid accounts due to a misconfiguration rather than credential theft. It also relates to data exfiltration techniques where sensitive information is accessed through seemingly benign endpoints like RSS feeds. The ease of exploitation means that automated scanning tools can easily identify and exploit these endpoints across multiple instances of the software, leading to widespread potential data breaches if left unpatched.
To mitigate this vulnerability, administrators must upgrade Admidio to version 5.0.12 or later where the access control logic has been corrected to enforce authentication on all relevant modules including their RSS feed counterparts. In environments where immediate patching is not feasible, temporary mitigations should include configuring web application firewalls to block direct GET requests to rss/forum.php and rss/announcements.php from unauthenticated sources. Additionally, reviewing other syndication endpoints for similar access control flaws is recommended to ensure comprehensive security posture. Regular audits of authentication mechanisms across all public-facing interfaces are essential to prevent recurrence of such misconfigurations in future updates or custom modules.