Executive Summary

CVE-2026-1879 is a vulnerability in Harvard University IQSS Dataverse up to version 6.8, specifically in the Theme Customization component's /ThemeAndWidgets.xhtml file. It allows an attacker to perform unrestricted file uploads by manipulating the uploadLogo argument. Although the client-side interface restricts uploads to image files, this validation can be bypassed by intercepting and modifying the HTTP upload request.

An attacker with permissions to edit a Dataverse (such as Administrator, Contributor, or Curator) can upload arbitrary Java Server Pages (JSP) files by changing the filename and content of the upload. This enables the attacker to upload a JSP web shell that allows execution of arbitrary commands on the server with the web server's privileges.

The uploaded JSP files are stored in directories like "/logos/temp/..." or "/logos/...". The web shell executes commands passed via HTTP parameters and returns the output, enabling remote code execution and potentially full server compromise.

The vulnerability is remotely exploitable, the exploit is public, and upgrading to Dataverse version 6.10 mitigates the issue.

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Impact Analysis

This vulnerability can have severe impacts including allowing an attacker to execute arbitrary commands on the server hosting the Dataverse application.

• Full server compromise due to remote code execution.
• Unauthorized access to databases and sensitive data.
• Lateral movement within the network, potentially compromising other systems.
• Persistent access through uploaded web shells, making removal difficult.

Because the exploit is public and the vulnerability allows unrestricted file upload, attackers can easily exploit this if the system is not upgraded or properly secured.

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Detection Guidance

This vulnerability can be detected by checking for unauthorized or suspicious JSP files uploaded in the directories used for logo uploads, such as "/logos/temp/" or "/logos/". Since the exploit involves uploading JSP web shells that allow command execution, monitoring these directories for unexpected .jsp files is critical.

Network detection can involve monitoring HTTP requests for unusual file upload activity, especially uploads that bypass client-side restrictions on image file types.

Suggested commands to detect the presence of uploaded JSP web shells on the server include:

• Find JSP files in logo upload directories: `find /path/to/dataverse/logos/ -name '*.jsp'`
• Check web server access logs for requests to suspicious JSP files, e.g., `grep ".jsp" /var/log/apache2/access.log` or equivalent.
• Use network monitoring tools or IDS to detect HTTP POST requests with manipulated uploadLogo parameters or unusual file upload patterns.

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Mitigation Strategies

The primary immediate mitigation step is to upgrade the affected Dataverse component to version 6.10, which includes a fix for this vulnerability.

Until the upgrade can be applied, administrators should:

• Audit and remove any unauthorized JSP files found in the logo upload directories.
• Restrict permissions to only trusted users who can upload logos or modify themes.
• Monitor web server logs and network traffic for suspicious activity related to file uploads.
• Consider temporarily disabling the theme customization upload feature if possible.

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Compliance Impact

The provided information does not explicitly address how CVE-2026-1879 impacts compliance with common standards and regulations such as GDPR or HIPAA.

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