CVE-2026-90857: College Notes Gallery Auth Bypass Flaw

CVE-2026-90857 Overview

CVE-2026-90857 is an unrestricted file upload vulnerability in SourceCodester College Notes Gallery Management System 1.0. The flaw resides in the /dashboard/userprofile.php script, specifically in the Profile Upload component. Attackers can manipulate the image parameter to upload files without adequate restrictions on file type or content. The attack is remotely exploitable and requires only low-level privileges (an authenticated user account). Public exploit details have been disclosed, increasing the likelihood of opportunistic abuse against exposed instances. The weakness is classified under CWE-284: Improper Access Control.

Critical Impact
Remote authenticated attackers can upload arbitrary files through the profile image function, potentially staging web shells or other malicious content on the hosting server.

Affected Products

SourceCodester College Notes Gallery Management System 1.0
The /dashboard/userprofile.php script (Profile Upload component)
The image parameter handling logic

Discovery Timeline

2026-09-15 - CVE-2026-90857 published to the National Vulnerability Database (NVD)
2026-09-15 - Last updated in NVD database

Technical Details for CVE-2026-90857

Vulnerability Analysis

The vulnerability is an unrestricted file upload flaw affecting the user profile management workflow of the College Notes Gallery Management System. The /dashboard/userprofile.php handler accepts input via the image parameter without validating file extensions, MIME types, or file content signatures. An authenticated attacker can submit a crafted multipart request containing executable server-side code, such as a PHP web shell disguised as an image. Because the affected component is reachable over the network and requires only standard user privileges, the barrier to exploitation is low. Public exploit information has been released, which typically leads to inclusion in commodity scanning tools.

Root Cause

The root cause is improper access control combined with missing file validation in the profile upload logic [CWE-284]. The application trusts client-supplied metadata for the image parameter and writes the payload to a location accessible by the web server without enforcing an allow-list of extensions or performing content inspection. This design permits arbitrary file placement under a directory the PHP interpreter may execute.

Attack Vector

Exploitation requires an authenticated session on the application. The attacker navigates to the profile page, intercepts the profile update request, and replaces the intended image file with a server-executable payload. After upload, the attacker requests the stored file directly through the web server. If the file resides in a script-executable path, the payload runs in the context of the web server process. Detailed exploitation notes are referenced in the VulDB entry for CVE-2026-90857 and the associated GitHub issue.

No verified proof-of-concept code is included in this article. Refer to the VulDB vulnerability record #403414 for technical exploitation details.

Detection Methods for CVE-2026-90857

Indicators of Compromise

Files with non-image extensions (.php, .phtml, .phar) present in profile image upload directories used by the application.
HTTP POST requests to /dashboard/userprofile.php containing multipart payloads where the image field carries executable content or double extensions such as avatar.php.jpg.
Outbound network connections or shell command execution originating from the PHP-FPM or Apache worker process after profile updates.

Detection Strategies

Inspect web server access logs for GET requests directly targeting files inside the profile upload directory, particularly those returning non-image content types.
Deploy web application firewall (WAF) rules that block uploads whose declared MIME type conflicts with the file's magic bytes.
Correlate authenticated profile edits with subsequent process spawns from the web server user (for example, sh, bash, nc, python).

Monitoring Recommendations

Enable file integrity monitoring on the web root and upload directories to alert on new script files.
Log all requests to /dashboard/userprofile.php with full parameter capture for retrospective hunting.
Alert on any first-seen executable file type appearing in directories designated for user-supplied media.

How to Mitigate CVE-2026-90857

Immediate Actions Required

Restrict access to /dashboard/userprofile.php at the reverse proxy or WAF layer until the application is patched or replaced.
Configure the web server to disable PHP execution within the upload directory using a directory-level handler override.
Audit existing upload directories for unexpected files and remove any that are not legitimate image content.

Patch Information

At the time of publication, no vendor patch has been referenced in the NVD entry or the SourceCodester project site. Organizations using College Notes Gallery Management System 1.0 should treat the application as unpatched and apply compensating controls until an official fix is available.

Workarounds

Enforce a server-side allow-list restricting uploads to validated image extensions (.jpg, .jpeg, .png, .gif) and verify file signatures before writing to disk.
Rename uploaded files to random identifiers and strip any original extension to prevent script execution based on filename.
Serve user-uploaded content from a separate domain or storage backend that does not execute server-side code.
Require re-authentication and CSRF protection on the profile upload endpoint to reduce the attack surface.

bash

# Apache configuration to disable script execution in the uploads directory
<Directory "/var/www/college-notes/dashboard/uploads">
    php_admin_flag engine off
    AddType text/plain .php .phtml .phar .php3 .php4 .php5 .php7
    <FilesMatch "\.(php|phtml|phar|php[3-7])$">
        Require all denied
    </FilesMatch>
</Directory>