Executive Summary

CVE-2026-24010 is a critical file upload vulnerability in Horilla versions prior to 1.5.0. Authenticated users with permission to update profile photos can upload a malicious HTML file disguised as a profile picture by manipulating file extensions and headers. This uploaded file acts as a phishing page hosted on Horilla's domain, showing victims a realistic "Session Expired" login prompt that captures their credentials and sends them to the attacker. This enables attackers to steal user credentials and take over accounts. [1]

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Impact Analysis

This vulnerability can lead to account takeover by harvesting user credentials through phishing hosted on the legitimate Horilla domain. Attackers can gain unauthorized access to sensitive HR data such as employee personal information, payroll records, and administrative controls. The impact includes data breaches, financial fraud, and operational disruption. [1]

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Detection Guidance

This vulnerability can be detected by checking for the presence of malicious HTML files uploaded as profile pictures by authenticated users with profile photo update permissions. One can look for files with suspicious extensions or content types that are HTML but disguised as images. Additionally, monitoring network traffic for unusual outbound connections to attacker-controlled servers when users enter credentials on suspicious URLs can help detect exploitation. A practical approach includes listing uploaded profile pictures and inspecting their file types and contents. For example, commands to find HTML files in the upload directory might include: `find /path/to/uploads -type f \( -name '*.html' -o -name '*.htm' \)` or using `file` command to detect files with HTML content masquerading as images. Network monitoring tools or running a listener like `netcat` on expected ports can help detect credential exfiltration attempts. [1]

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Mitigation Strategies

The immediate mitigation step is to upgrade Horilla to version 1.5.0 or later, where this vulnerability has been patched. Additionally, restrict profile photo update permissions to trusted users only, and implement strict validation and sanitization of uploaded files to prevent HTML or other executable content from being uploaded as images. Monitoring and removing any suspicious uploaded files and educating users about phishing risks can also help reduce impact. [1, 2]

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Compliance Impact

This vulnerability enables attackers to perform account takeover and potentially access sensitive HR data such as employee personal information and payroll records. Such unauthorized access and data breaches could lead to non-compliance with data protection regulations like GDPR and HIPAA, which require safeguarding personal and sensitive information. Therefore, exploitation of this vulnerability may result in violations of these standards due to compromised confidentiality and unauthorized data exposure. [1]

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