CVE-2026-1879 Overview
A vulnerability has been identified in Harvard University IQSS Dataverse versions up to 6.8 that allows unrestricted file upload through the Theme Customization component. This affects the /ThemeAndWidgets.xhtml endpoint, specifically through manipulation of the uploadLogo argument. The vulnerability enables remote exploitation and could allow attackers to upload malicious files to affected Dataverse installations.
Critical Impact
Remote attackers with low privileges can exploit the unrestricted upload functionality to potentially upload malicious files, which could lead to further compromise of the affected system.
Affected Products
- Harvard University IQSS Dataverse versions up to 6.8
- Dataverse Theme Customization component (/ThemeAndWidgets.xhtml)
Discovery Timeline
- 2026-04-01 - CVE CVE-2026-1879 published to NVD
- 2026-04-01 - Last updated in NVD database
Technical Details for CVE-2026-1879
Vulnerability Analysis
This vulnerability stems from improper access control (CWE-284) in the Dataverse Theme Customization functionality. The affected endpoint /ThemeAndWidgets.xhtml processes logo uploads through the uploadLogo parameter without proper validation or restrictions on the uploaded file types. This allows authenticated users with low privileges to upload arbitrary files to the server.
The network-accessible nature of this vulnerability means it can be exploited remotely by any authenticated user. While the immediate confidentiality, integrity, and availability impacts are limited, the ability to upload unrestricted files creates a foundation for more severe attacks, including potential remote code execution if uploaded files can be executed by the server.
Root Cause
The root cause is improper access control and missing file upload validation in the Theme Customization component. The uploadLogo function fails to adequately restrict the types of files that can be uploaded and does not properly verify that the uploaded content matches expected logo file formats. This lack of input validation on file uploads allows attackers to bypass intended restrictions.
Attack Vector
The attack is conducted remotely over the network against the /ThemeAndWidgets.xhtml endpoint. An authenticated attacker with low privileges can:
- Access the Theme Customization interface
- Manipulate the uploadLogo parameter to upload arbitrary files
- Bypass file type restrictions that should limit uploads to legitimate image formats
The exploit for this vulnerability is publicly available. For technical details on the exploitation mechanism, refer to the GitHub Gist PoC.
Detection Methods for CVE-2026-1879
Indicators of Compromise
- Unexpected files appearing in logo upload directories that are not valid image formats
- Anomalous HTTP POST requests to /ThemeAndWidgets.xhtml with unusual file types
- Log entries showing multiple upload attempts or uploads from unexpected user accounts
Detection Strategies
- Monitor web application logs for POST requests to /ThemeAndWidgets.xhtml containing non-image file extensions
- Implement file integrity monitoring on directories where uploaded logos are stored
- Review access logs for Theme Customization features by unauthorized or unusual user accounts
Monitoring Recommendations
- Enable detailed logging for the Theme Customization component in Dataverse
- Set up alerts for file uploads that fail validation or contain suspicious content
- Monitor for any executable or script files uploaded through the logo upload functionality
- Implement network-level monitoring for unusual traffic patterns to the affected endpoint
How to Mitigate CVE-2026-1879
Immediate Actions Required
- Upgrade Harvard University IQSS Dataverse to version 6.10 or later immediately
- Review recently uploaded files in the logo directory for suspicious content
- Audit user accounts with access to Theme Customization features
- Consider temporarily disabling the Theme Customization functionality until patching is complete
Patch Information
Harvard University IQSS has released Dataverse version 6.10 which addresses this vulnerability. The vendor responded professionally and quickly released a fixed version. Organizations should upgrade to Dataverse v6.10 to remediate this issue.
Additional details are available at VulDB.
Workarounds
- Restrict access to the Theme Customization interface to only trusted administrators
- Implement web application firewall (WAF) rules to filter suspicious file uploads to /ThemeAndWidgets.xhtml
- Add server-side file type validation at the web server or reverse proxy level
- Disable the logo upload functionality if not required for operations
# Example: Restrict access to ThemeAndWidgets.xhtml via Apache configuration
<Location "/ThemeAndWidgets.xhtml">
Require ip 10.0.0.0/8
Require ip 192.168.0.0/16
</Location>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
