CVE-2026-55736

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. High risk of data tampering.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-23 19:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-25 23:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-23 19:17 UTC

Last modified

2026-10-25 23:10 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-915

Record status

Deferred

Attack profile CVSS 4.0 · 5.9

Attack vector

Local

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-55736.md and follow it. Check whether this project is affected by CVE-2026-55736. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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