CVE-2026-54004 in Kirby
Summary
by MITRE • 07/09/2026
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites with content.fileRedirects enabled could redirect unauthenticated clean file URL requests for files stored in top-level draft pages to physical media URLs without checking page access permissions or preview tokens, leading to disclosure of draft file contents. This issue is fixed in versions 4.9.4 and 5.4.4.
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Analysis
by VulDB Data Team • 07/09/2026
This vulnerability affects Kirby CMS installations where the content.fileRedirects feature is enabled, creating a critical access control flaw that allows unauthorized users to bypass authentication mechanisms. The vulnerability stems from insufficient permission validation when processing clean file URL requests for files located within top-level draft pages. Attackers can exploit this weakness by crafting malicious requests that target specific file paths, potentially gaining access to sensitive content that should remain restricted to authorized users only.
The technical implementation flaw resides in the file redirect handling logic which fails to verify whether the requesting user possesses proper authorization to access the targeted draft page contents. This represents a classic privilege escalation vulnerability where unauthenticated users can traverse the system's access control boundaries through carefully constructed URL parameters. The flaw specifically impacts files stored in top-level draft pages, meaning that content creators who have not yet published their work remain vulnerable until proper authentication checks are implemented.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to access unpublished content, draft documents, and potentially sensitive media files that should only be visible to authenticated users with appropriate permissions. This exposure can lead to competitive intelligence theft, intellectual property disclosure, or the compromise of confidential business information that has not yet been made public. The vulnerability affects both version 4.9.x and 5.4.x branches of Kirby CMS, indicating a widespread issue affecting multiple release lines.
Security researchers would categorize this as a CWE-285: Improper Authorization vulnerability, which falls under the broader category of access control failures in the OWASP Top Ten security risks. The issue demonstrates poor input validation and inadequate access control mechanisms that allow unauthorized information disclosure through file path traversal techniques. From an ATT&CK framework perspective, this vulnerability maps to T1078: Valid Accounts and T1566: Phishing, as it enables attackers to gain access to content through legitimate system pathways without requiring additional credential compromise.
Organizations using Kirby CMS should immediately implement the patched versions 4.9.4 and 5.4.4 to address this vulnerability, while also reviewing their current file redirect configurations and access control policies. System administrators should ensure that all draft content remains properly protected and that file redirect features are configured with appropriate security checks. Additionally, organizations should consider implementing network-level monitoring to detect unusual patterns of file access attempts that might indicate exploitation attempts against this vulnerability. The fix addresses the core permission validation issue by ensuring that all file redirect requests undergo proper authentication and authorization checks before any content is served to requesting users.