CVE-2026-55736
Received Received - Intake
Improper Object Attribute Control in Ash Framework

Publication date: 2026-06-23

Last updated on: 2026-06-23

Assigner: EEF

Description
Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerability in ash-project ash allows a user to set the value of a private action argument that is intended to be controlled only by trusted server-side code. Action arguments declared with public?: false are meant to be set internally (for example via Ash.Changeset.set_private_argument/3) and must not be settable from end-user input. When a changeset is built from a parameter map, Ash filters out private arguments, but the filtering is incomplete. In the regular changeset path (for_create, for_update, for_destroy), private arguments are stripped only when the parameter key is an atom. When the key is a binary (string), as is the case for user-supplied parameters, the private argument is kept and the user controls its value. In the atomic path (Ash.Changeset.fully_atomic_changeset/4, also reached through atomic and bulk updates), private arguments are not stripped at all, regardless of whether the key is an atom or a binary. An attacker who can submit parameters to an action that defines a private argument can therefore inject a value for that argument. Depending on how the application uses the argument (for example an acting_user_id driving authorization or record ownership), this can lead to an integrity violation or privilege escalation. This issue affects ash: from 3.0.0 before 3.29.3.
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Meta Information
Published
2026-06-23
Last Modified
2026-06-23
Generated
2026-06-24
AI Q&A
2026-06-23
EPSS Evaluated
N/A
NVD
CVE-2026-55736
EUVD
EUVD-2026-38570
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
ash-project ash From 3.0.0 (inc) to 3.29.3 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-915 The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.
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Compliance Impact

This vulnerability allows unauthorized modification of private action arguments that can control authorization, identity, or record ownership, potentially leading to integrity violations or privilege escalation.

Such unauthorized access and manipulation of sensitive data or control parameters could negatively impact compliance with standards and regulations like GDPR or HIPAA, which require strict controls over data integrity, access, and authorization.

However, the provided information does not explicitly state the direct impact on compliance with these standards.

Executive Summary

This vulnerability exists in the Ash framework versions 3.0.0 to before 3.29.3 and involves improper control over private action arguments. These private arguments, which are intended to be set only by trusted server-side code, can be manipulated by user input due to incomplete filtering.

Specifically, when a changeset is built from user-supplied parameters, Ash filters out private arguments only if the parameter key is an atom. However, if the key is a binary (string), which is common in user input, the private argument is not filtered out and can be set by the user. In atomic or bulk update paths, private arguments are never stripped regardless of key type.

As a result, an attacker can inject values for private arguments that should be controlled internally, potentially leading to unauthorized modifications.

Impact Analysis

Exploiting this vulnerability allows an attacker to inject values into private action arguments that are meant to be controlled only by trusted server-side code.

Depending on how these private arguments are used in the application—for example, if they control authorization, identity, or record ownership—this can lead to integrity violations or privilege escalation.

  • Integrity violation: unauthorized modification of data or state.
  • Privilege escalation: gaining higher access rights than intended.
Mitigation Strategies

To mitigate this vulnerability, you should upgrade the Ash framework to version 3.29.3 or later, where the issue has been fixed.

The fix ensures that private action arguments declared with public?: false cannot be set from user input, whether the parameters are string-keyed or atom-keyed.

Additionally, review your application code to ensure that private arguments are not exposed or modifiable from untrusted sources, especially in changeset creation and atomic or bulk update paths.

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