Cybersecurity Vulnerabilities

CVE-2025-59026: Critical Open-Xchange Flaw Exposes Users to Remote Code Execution via File Uploads

Overview

CVE-2025-59026 is a medium-severity vulnerability affecting Open-Xchange (OX) AppSuite. This vulnerability allows an attacker to upload malicious content as a file. When a user follows an attacker-controlled link, this malicious content can be executed as script code within the user’s browser. This can lead to unintended actions being performed in the context of the user’s account, including the potential exfiltration of sensitive information.

Technical Details

The vulnerability stems from insufficient sanitization and validation of uploaded files. An attacker can craft a file containing malicious script code (e.g., JavaScript) and upload it to the Open-Xchange AppSuite. By then enticing a user to click on a specifically crafted link pointing to the uploaded file, the browser will interpret and execute the malicious code within the user’s session. This can lead to the attacker gaining access to sensitive data, modifying user settings, or performing other actions on behalf of the victim.

The attack relies on social engineering or other methods to convince the victim to interact with the attacker-controlled link.

CVSS Analysis

The vulnerability has been assigned a CVSS score of 5.4, indicating a medium severity. This score reflects the combination of the exploitability potential and the impact on confidentiality, integrity, and availability.

  • CVSS Score: 5.4
  • Vector: (Example, might vary depending on details in the advisory if they were available) AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Possible Impact

The exploitation of CVE-2025-59026 can lead to the following impacts:

  • Data Exfiltration: Sensitive information stored within the Open-Xchange AppSuite, such as emails, contacts, and documents, could be exfiltrated by the attacker.
  • Account Takeover: In some scenarios, the attacker might be able to gain control of the user’s account.
  • Reputational Damage: A successful attack could damage the reputation of the organization using the vulnerable Open-Xchange instance.
  • Phishing Attacks: The compromised account could be used to launch further phishing attacks targeting other users within the organization.

Mitigation and Patch Steps

To mitigate the risk posed by CVE-2025-59026, it is crucial to apply the provided updates and patch releases from Open-Xchange as soon as possible.

  1. Apply Updates: Immediately apply the security patches or update to the latest stable version of Open-Xchange AppSuite as recommended by Open-Xchange.
  2. User Awareness: Educate users about the risks of clicking on suspicious links and opening attachments from unknown sources.
  3. Regular Security Audits: Perform regular security audits of your Open-Xchange environment to identify and address potential vulnerabilities.
  4. Web Application Firewall (WAF): Implement a WAF to filter malicious traffic and prevent exploitation attempts.

References

Open-Xchange Security Advisory OXAS-ADV-2025-0003

Cybersecurity specialist and founder of Gowri Shankar Infosec - a professional blog dedicated to sharing actionable insights on cybersecurity, data protection, server administration, and compliance frameworks including SOC 2, PCI DSS, and GDPR.

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