CVE-2026-82725 in ash_phoenix
Summary
by MITRE • 08/31/2026
Authorization Bypass Through User-Controlled Key vulnerability in ash-project ash_phoenix lets an attacker who controls filter form parameters filter across relationships the resource author marked non-public, turning the returned rows into a boolean oracle over private related data.
AshPhoenix.FilterForm resolved every relationship hop in the user-supplied path with Ash.Resource.Info.related/2, which traverses private relationships, and only checked the terminal field for publicity. parse_path_and_field/2 also rewrote a field naming a relationship into an extra path segment, so field=some_private_rel was accepted too. Both path and field come straight from form params, and the resulting ref went to Ash.Query.do_filter/2 without the public-only enforcement of Ash.Filter.parse_input/2. The fix resolves each hop with Ash.Resource.Info.public_relationship/2, rejecting the first non-public hop, and requires the terminal field to be public.
This issue affects ash_phoenix: from 0.6.0-rc.1 before 2.3.25.
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Analysis
by VulDB Data Team • 08/31/2026
The vulnerability identified in AshPhoenix versions prior to 2.3.25 represents a critical authorization bypass mechanism rooted in improper access control enforcement within the filtering subsystem. Specifically, this flaw allows an attacker who has the ability to supply filter form parameters to traverse relationships that were explicitly marked as non-public by the resource author. By manipulating these inputs, the attacker can effectively turn the returned rows into a boolean oracle for private related data, thereby exposing sensitive information that should remain inaccessible under normal operational constraints. This type of vulnerability is classified under CWE-284 Improper Access Control and aligns with ATT&CK techniques involving unauthorized access to restricted resources or privilege escalation through logical flaws in application logic.
The technical root cause lies in the implementation details of AshPhoenix.FilterForm, which processes user-supplied paths for filtering operations. The function parse_path_and_field/2 was designed to rewrite field names that reference relationships into extra path segments, allowing inputs such as field=some_private_rel to be accepted without sufficient validation. When resolving these relationship hops, the system utilized Ash.Resource.Info.related/2, a method that traverses all defined relationships regardless of their visibility settings. Crucially, the code only performed a publicity check on the terminal field in the path rather than validating each intermediate hop along the traversal chain. This oversight meant that while the final data point might have been public or correctly checked, the pathway to reach it through private associations remained open to exploitation.
Furthermore, the resulting reference generated from these unchecked paths was passed directly to Ash.Query.do_filter/2 without applying the stricter enforcement logic found in Ash.Filter.parse_input/2. The latter function is designed to enforce public-only constraints during filter parsing, but its absence in this specific code path created a significant security gap. Because both the relationship path and field parameters originate directly from user-controlled form inputs, an attacker can craft requests that bypass intended privacy boundaries. This lack of granular validation at every step of the relationship traversal enables the extraction of private data through indirect means, effectively circumventing the application's access control policies.
The operational impact of this vulnerability is severe, as it compromises the confidentiality of related data structures within Ash resources. Attackers can enumerate and extract information from relationships that were intentionally hidden or restricted by developers. This capability not only violates user privacy expectations but also undermines the integrity of the application’s security model. In environments where sensitive business logic relies on strict separation between public and private data associations, this flaw could lead to significant data breaches, regulatory non-compliance, and loss of trust among users who expect their private information to remain secure from unauthorized access attempts.
To mitigate this vulnerability, it is essential to upgrade AshPhoenix to version 2.3.25 or later, where the issue has been resolved by implementing stricter validation logic. The fix ensures that each hop in a relationship path is validated using Ash.Resource.Info.public_relationship/2 rather than the more permissive related function. This change guarantees that if any segment of the traversal chain involves a non-public relationship, the request is immediately rejected before proceeding further. Additionally, the updated code enforces that the terminal field must also be public, ensuring comprehensive coverage across all stages of data access. Organizations relying on AshPhoenix should prioritize this update to restore proper authorization controls and prevent unauthorized traversal of private relationships through form-based filtering mechanisms.