CVE-2025-25009 Overview
CVE-2025-25009 is a stored Cross-Site Scripting (XSS) vulnerability in Elastic Kibana. The flaw exists in the case file upload feature, where Kibana fails to properly neutralize user-supplied input during web page generation. An authenticated attacker with low privileges can upload a case attachment containing malicious script content. When another user views the case, the injected script executes in their browser session. The vulnerability is classified under CWE-79 and affects confidentiality and integrity at a limited scope. Elastic addressed the issue in Kibana 8.18.8, 8.19.5, 9.0.8, and 9.1.5 under advisory ESA-2025-20.
Critical Impact
Authenticated low-privilege users can inject persistent JavaScript through case file uploads, executing arbitrary script in the browsers of other Kibana users who access the affected case.
Affected Products
- Elastic Kibana versions prior to 8.18.8
- Elastic Kibana versions prior to 8.19.5 and 9.0.8
- Elastic Kibana versions prior to 9.1.5
Discovery Timeline
- 2025-10-07 - CVE-2025-25009 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-25009
Vulnerability Analysis
The vulnerability resides in Kibana's case management feature, specifically the file upload handling path for case attachments. Kibana renders attachment metadata and content in the user interface without sufficiently sanitizing or encoding untrusted input. An attacker uploads a file whose filename or content includes HTML or JavaScript payloads. Because the payload is stored server-side and later rendered inline to viewers, execution occurs in the security context of the Kibana origin.
Exploitation requires the attacker to hold an authenticated Kibana account with permission to create or modify cases. A victim user must then open the case containing the malicious attachment, satisfying the user interaction requirement. Successful execution allows the attacker to read data accessible to the victim, perform actions on the victim's behalf, or pivot into cross-application impact through the changed scope.
Root Cause
The root cause is improper output encoding of case attachment fields rendered in Kibana's web interface. Kibana treats attacker-controlled attachment data as trusted markup rather than escaping it before injection into the DOM. This maps directly to CWE-79, Improper Neutralization of Input During Web Page Generation.
Attack Vector
Exploitation is network-based and requires authentication plus victim interaction. The attacker submits a crafted attachment through the case file upload API. The stored payload triggers when any authorized user browses the affected case, delivering the script to the victim's browser without any additional attacker action.
No verified public proof-of-concept has been released. See the Elastic Security Update ESA-2025-20 for advisory details.
Detection Methods for CVE-2025-25009
Indicators of Compromise
- Case attachments whose filenames or metadata contain HTML tags, <script> fragments, or javascript: URIs.
- Kibana audit log entries showing case attachment creation followed by unusual outbound requests from viewer sessions.
- Anomalous session token usage originating from Kibana users shortly after they viewed a specific case.
Detection Strategies
- Enable Kibana audit logging and alert on case_user_action events that include attachment creation from non-administrative users.
- Inspect stored case attachment records for filenames or content fields containing angle brackets or scripting keywords.
- Correlate browser telemetry from privileged Kibana users with case-view events to identify unexpected script execution.
Monitoring Recommendations
- Forward Kibana audit logs and reverse proxy access logs to a centralized analytics platform for retention and search.
- Monitor for unexpected DOM-level changes or outbound requests from the Kibana origin using content security policy (CSP) violation reports.
- Track upgrade status of all Kibana instances against the fixed versions to identify unpatched deployments.
How to Mitigate CVE-2025-25009
Immediate Actions Required
- Upgrade Kibana to 8.18.8, 8.19.5, 9.0.8, or 9.1.5 or later, matching your deployment branch.
- Review case attachment inventories for suspicious filenames or content submitted before the upgrade.
- Restrict case creation and attachment permissions to trusted roles until patching is complete.
Patch Information
Elastic released fixed Kibana versions 8.18.8, 8.19.5, 9.0.8, and 9.1.5 under advisory ESA-2025-20. Refer to the Elastic Security Update ESA-2025-20 for full upgrade guidance and version mapping.
Workarounds
- Remove or restrict the case attachment upload privilege via Kibana role-based access control until the patch is applied.
- Enforce a strict Content Security Policy on the Kibana origin to limit inline script execution.
- Rotate Kibana user session tokens and API keys if suspicious attachments are found in existing cases.
# Configuration example: restrict case attachment permissions
# In Kibana role definitions, remove the following privilege from low-trust roles:
# feature.cases.all
# Grant read-only access instead:
# feature.cases.read
# Apply via Kibana Stack Management > Roles or the role API.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
