CVE-2026-78075 Overview
CVE-2026-78075 is a Broken Object-Level Authorization (BOLA) vulnerability in the JoomShaper Helix Ultimate template for Joomla, affecting versions prior to 2.2.10. The flaw resides in the Blog::remove_image() function, which validates whether the authenticated user can edit a supplied article ID but fails to verify that the referenced image path actually belongs to that article. On Joomla 3 builds where physical file deletion is triggered, an authenticated author can pair a legitimate article ID with an arbitrary file path under /images/ to delete files outside the article's scope. The weakness is categorized as [CWE-639] Authorization Bypass Through User-Controlled Key.
Critical Impact
Authenticated authors can delete arbitrary files under the Joomla /images/ directory, causing integrity and availability loss on affected sites.
Affected Products
- JoomShaper Helix Ultimate template versions prior to 2.2.10
- Joomla 3 sites using Helix Ultimate where physical file deletion is triggered
- Joomla installations with author-level (or higher) content permissions
Discovery Timeline
- 2026-08-31 - CVE-2026-78075 published to NVD
- 2026-08-31 - Last updated in NVD database
Technical Details for CVE-2026-78075
Vulnerability Analysis
The vulnerability exists in the Blog::remove_image() method within Helix Ultimate. The function accepts two attacker-controlled inputs: an article ID and an image source path (src). Server-side logic checks that the requesting user has edit permissions for the article ID, but it does not check whether the src value corresponds to an image actually referenced by that article.
On Joomla 3 builds, remove_image() proceeds to delete the file at the supplied path from disk. Because the path is trusted after the article-permission check succeeds, an authenticated author can substitute a valid article ID they own with an arbitrary file path rooted under /images/. The mismatch between the authorization boundary (article ownership) and the resource being acted upon (file path) is the essence of the BOLA class of flaws.
Root Cause
The root cause is a missing linkage between the authorization check and the target object. Blog::remove_image() treats the article ID as the sole authorization anchor, then operates on a separately supplied file path without confirming the two are related. This is a textbook Broken Object-Level Authorization pattern, cataloged as [CWE-639].
Attack Vector
Exploitation requires an authenticated Joomla account with permission to edit at least one article, such as the Author role. The attacker issues a request to the remove_image endpoint containing an article ID they legitimately control and a src parameter pointing to any file under /images/. The server validates the article permission, then deletes the referenced file. Repeated requests can remove media, template assets, or other resources stored under /images/, resulting in site defacement or broken functionality.
No verified public exploit code is available. Refer to the JoomShaper Helix Ultimate Template advisory for vendor-supplied technical details.
Detection Methods for CVE-2026-78075
Indicators of Compromise
- Unexpected deletion of files under the Joomla /images/ directory that are not referenced by the article context of the requesting user.
- HTTP requests to the Helix Ultimate remove_image action where the src parameter path does not match any image embedded in the referenced article.
- Author-role accounts issuing high volumes of image deletion requests across multiple unrelated article IDs.
Detection Strategies
- Inspect Joomla access logs for POST requests invoking Blog::remove_image() and correlate the src parameter against the article's stored HTML content.
- Enable Joomla User Actions Log and audit content-editing activity by author-tier accounts.
- Monitor filesystem change events on the /images/ tree and alert on deletions that occur outside administrative maintenance windows.
Monitoring Recommendations
- Forward web server, Joomla application, and filesystem audit logs to a centralized logging platform for correlation.
- Baseline normal image deletion volumes per user role and alert on statistical deviations.
- Track version banners of the Helix Ultimate template across managed Joomla instances to identify unpatched deployments.
How to Mitigate CVE-2026-78075
Immediate Actions Required
- Upgrade Helix Ultimate to version 2.2.10 or later on all Joomla sites where the template is installed.
- Audit author, editor, and publisher accounts and revoke access for unused or untrusted users.
- Restore any files deleted through unauthorized remove_image requests from backups.
Patch Information
JoomShaper resolved the issue in Helix Ultimate 2.2.10 by ensuring the image path passed to Blog::remove_image() is validated against the referenced article before deletion. Administrators should apply the update through Joomla Extension Manager or download the current release from the JoomShaper Helix Ultimate Template page.
Workarounds
- Restrict the Author, Editor, and Publisher user groups to trusted personnel until the template is upgraded.
- Deploy a web application firewall rule that blocks or reviews remove_image requests whose src parameter contains path components outside the expected article media directory.
- Set restrictive filesystem permissions on /images/ subdirectories that contain shared or template-owned assets, limiting write access from the Joomla process where practical.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
