CVE-2026-44956 Overview
CVE-2026-44956 is a stored cross-site scripting (XSS) vulnerability [CWE-79] that allows low-privileged users to inject malicious JavaScript through their Full Name field. The application includes the user's Full Name in system-generated emails. The email content is then stored in the details field of the userlog table. When an administrator views these entries through userlog-details.php, the missing output sanitisation causes the injected payload to execute in the admin's browser context.
Critical Impact
A low-privileged authenticated user can execute arbitrary JavaScript in an administrator's session, enabling session theft, privileged action abuse, and lateral compromise of the application.
Affected Products
- Application exposing the userlog-details.php administrative view (vendor and product not specified in the NVD entry)
- Versions prior to the fix that adds proper escaping to the userlog details output
Discovery Timeline
- 2026-06-23 - CVE-2026-44956 published to NVD
- 2026-06-23 - Last updated in NVD database
Technical Details for CVE-2026-44956
Vulnerability Analysis
The flaw is a second-order stored XSS. A low-privileged user sets their Full Name to a value containing an HTML or JavaScript payload. The application accepts the value without sanitising it for downstream HTML contexts. The Full Name is then embedded in system-generated emails sent for routine account or workflow events.
The full email content, including the attacker-controlled name, is persisted to the details column of the userlog table. When an administrator opens userlog-details.php to review log entries, the stored content is rendered directly into the response HTML. Because the output is not escaped, the browser parses the payload as markup and executes it under the administrator's origin.
The attack requires no special privileges beyond an authenticated low-privileged account. Exploitation is asynchronous and depends on an administrator viewing the affected log entry.
Root Cause
The root cause is missing output encoding when rendering the details field in userlog-details.php. User-supplied content traversed the email subsystem and the database without contextual escaping. The fix adds proper escaping on the userlog details output rather than sanitising at input, which is the appropriate location for HTML-context defence.
Attack Vector
The attack vector is network-based and requires authentication as a low-privileged user. The attacker updates their profile Full Name to include a JavaScript payload such as a <script> tag or an event handler within an HTML element. The attacker then triggers any workflow that generates a system email referencing their account. The payload is stored automatically and waits for an administrator to view userlog-details.php.
No direct interaction with the administrator is required beyond their routine review of the user activity log.
Detection Methods for CVE-2026-44956
Indicators of Compromise
- Entries in the userlog table where the details field contains HTML tags such as <script>, <img, <svg, or inline event handlers like onerror= and onload=
- User profiles where the Full Name field contains angle brackets, quotes, or JavaScript keywords
- Unexpected outbound requests from administrator browsers shortly after viewing userlog-details.php
Detection Strategies
- Query the userlog.details column for HTML control characters and known XSS payload patterns and review matches manually.
- Inspect user account tables for Full Name values containing <, >, ", ', or javascript: substrings.
- Review web server access logs for repeated requests to userlog-details.php followed by anomalous administrator activity such as new account creation or permission changes.
Monitoring Recommendations
- Enable Content Security Policy (CSP) reporting and monitor for script-src violations originating from administrative pages.
- Alert on administrative session tokens used from unexpected IP addresses or user agents.
- Track changes to the Full Name profile field and flag entries that contain markup characters.
How to Mitigate CVE-2026-44956
Immediate Actions Required
- Apply the upstream fix that adds proper escaping to the userlog details output.
- Audit existing userlog.details rows for stored payloads and remove or neutralise malicious entries before administrators view them.
- Reset administrator session tokens if log review occurred while vulnerable code was deployed.
Patch Information
The maintainers added proper output escaping in the userlog details rendering path. See the HackerOne Report #3669623 for technical details on the disclosed issue and the corresponding fix.
Workarounds
- Restrict the ability of low-privileged users to modify the Full Name field, or apply server-side validation that rejects markup characters.
- Deploy a strict Content Security Policy that disallows inline scripts on administrative pages to blunt payload execution.
- Temporarily restrict access to userlog-details.php to administrators on a hardened workstation until the patch is applied.
# Example CSP header to block inline script execution on admin pages
Content-Security-Policy: default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'none'
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
