CVE-2026-113655 in Apostrophe
Summary
by MITRE • 10/20/2026
ApostropheCMS is an open-source Node.js content management system. Prior to 4.33.0, an authenticated editor with legitimate edit rights on a pre-existing ordinary page nested under a restricted parent can use the same-parent page move operation to change sibling ranks without create authorization on that parent. The non-default nesting must already exist, and the bypass is limited to sibling ordering rather than arbitrary content modification, confidentiality loss, or creation of the restricted nesting. This issue is fixed in version 4.33.0.
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Analysis
by VulDB Data Team • 10/20/2026
ApostropheCMS represents a widely utilized open-source content management system built on Node.js, designed to facilitate digital asset and page organization through hierarchical structures. Within this architecture, administrators can define complex permission models that restrict access to specific sections of the site tree based on user roles or groups. These restrictions are typically enforced at the parent level, meaning that users without explicit create permissions for a given node should not be able to introduce new child pages into that section. However, prior to version 4.33.0, a logical flaw existed in how the system handled page reordering operations within these restricted hierarchies. This vulnerability allows an authenticated editor who possesses legitimate edit rights on existing content nested under a restricted parent node to manipulate the structural order of sibling pages without holding the necessary create authorization for that specific parent container.
The technical root cause of this issue lies in the validation logic governing the same-parent page move operation. When a user attempts to reorder pages, the system verifies whether the target location is within the allowed scope based on the current hierarchy and existing permissions. The flaw arises because the permission check focuses primarily on the edit capabilities for individual items rather than validating the structural integrity of the parent node against create privileges during reordering actions. Consequently, an attacker can exploit this gap by moving a page to a different position among its siblings within the restricted section. This action effectively alters the sibling rank or order without triggering the authorization check that would normally prevent new content creation in that area. The vulnerability is strictly limited to modifying the sequence of existing items; it does not permit arbitrary content modification, data exfiltration, or the actual insertion of new pages into the restricted nesting structure.
From an operational perspective, this weakness poses a moderate risk related to integrity and potentially availability depending on the application's reliance on specific page ordering for functionality or user experience. While the attacker cannot directly inject malicious code or steal sensitive data through this vector alone, they can disrupt site navigation by rearranging critical pages out of their intended positions. This could lead to confusion for end-users or interfere with workflows that depend on a predictable content structure. The impact is further constrained by the requirement that non-default nesting must already exist and that the attacker must have prior edit access to at least one page within the restricted area, which limits the attack surface significantly compared to unrestricted privilege escalation flaws.
To mitigate this vulnerability, organizations running ApostropheCMS should immediately upgrade to version 4.33.0 or later, where the developers have patched the permission validation logic for sibling reordering operations. Until an upgrade is feasible, administrators can implement compensating controls by restricting edit permissions more granularly, ensuring that users who do not require structural manipulation capabilities are denied even basic editing rights on pages within sensitive sections of the site tree. Additionally, monitoring audit logs for unusual patterns in page movement requests may help detect potential exploitation attempts before they cause significant disruption to content organization.
This vulnerability aligns with CWE-269, which describes Improper Privilege Management, as it involves a failure to enforce proper authorization checks during state-changing operations. It also relates to CWE-732, concerning Incorrect Permission Assignment for Critical Resource, specifically regarding the misconfiguration of access controls that allow actions beyond intended privileges. In terms of offensive security frameworks, this behavior is consistent with ATT&CK technique T1083, which covers File and Directory Discovery, although in this context it manifests as structural manipulation rather than simple discovery. The flaw highlights the importance of validating permissions not just for data creation but also for metadata and structural modifications within hierarchical systems to ensure comprehensive access control enforcement.