CVE-2026-26338 Overview
Hyland Alfresco Transformation Service contains a Server-Side Request Forgery (SSRF) vulnerability that allows unauthenticated attackers to manipulate server-side requests through the document processing functionality. This vulnerability enables attackers to force the server to make arbitrary HTTP requests to internal or external resources, potentially exposing sensitive internal services and data.
Critical Impact
Unauthenticated attackers can exploit the document processing feature to perform SSRF attacks, potentially accessing internal network resources, cloud metadata endpoints, and sensitive internal services without any authentication requirements.
Affected Products
- Hyland Alfresco Transformation Service
Discovery Timeline
- 2026-02-19 - CVE-2026-26338 published to NVD
- 2026-02-19 - Last updated in NVD database
Technical Details for CVE-2026-26338
Vulnerability Analysis
This Server-Side Request Forgery (SSRF) vulnerability (CWE-918) exists within the document processing functionality of the Hyland Alfresco Transformation Service. The vulnerability allows unauthenticated attackers to craft malicious requests that cause the server to initiate HTTP requests to arbitrary destinations. This is particularly dangerous because the requests originate from the server itself, potentially bypassing firewall rules and network segmentation controls.
The attack surface is accessible over the network without requiring any authentication or user interaction, making it exploitable by remote attackers. While the vulnerability allows limited impact to confidentiality and integrity, it does not directly affect availability.
Root Cause
The root cause of this vulnerability stems from insufficient validation and sanitization of user-controlled input in the document processing functionality. When the Transformation Service processes documents, it fails to properly validate URLs or resource references embedded within documents or processing requests. This allows attackers to specify arbitrary URLs that the server will subsequently request, enabling SSRF attacks.
Attack Vector
The attack is executed over the network by submitting specially crafted documents or requests to the Transformation Service. Since no authentication is required, an attacker can directly interact with the vulnerable endpoint. The attacker embeds malicious URLs within the document or processing parameters, which the server then fetches during the transformation process. Common attack scenarios include:
- Accessing cloud provider metadata endpoints (e.g., http://169.254.169.254/)
- Scanning internal network services and ports
- Interacting with internal REST APIs or databases
- Exfiltrating data through DNS or HTTP requests to attacker-controlled servers
For technical exploitation details and proof-of-concept information, refer to the VulnCheck Advisory.
Detection Methods for CVE-2026-26338
Indicators of Compromise
- Unusual outbound HTTP requests from the Alfresco Transformation Service to internal IP ranges or cloud metadata endpoints
- Requests to uncommon ports or internal service endpoints from the transformation server
- High volume of transformation requests containing URL references to internal resources
- Server logs showing requests to 169.254.169.254 or other metadata service IPs
Detection Strategies
- Monitor network traffic from the Alfresco Transformation Service for connections to internal network ranges or sensitive endpoints
- Implement web application firewall (WAF) rules to detect SSRF payloads in document processing requests
- Review application logs for transformation requests containing suspicious URL patterns or IP addresses
- Deploy network-level monitoring to detect anomalous connections from application servers to internal services
Monitoring Recommendations
- Enable detailed logging on the Alfresco Transformation Service to capture all incoming requests and outbound connections
- Configure alerting for any requests to cloud metadata endpoints or internal IP ranges
- Implement network segmentation monitoring to detect lateral movement attempts
- Use SentinelOne Singularity Platform to monitor for suspicious network behavior and process activity on systems running the Transformation Service
How to Mitigate CVE-2026-26338
Immediate Actions Required
- Restrict network access to the Alfresco Transformation Service to only trusted internal systems
- Implement firewall rules to block outbound requests from the Transformation Service to sensitive internal resources
- Apply URL allowlisting to restrict document processing to approved domains only
- Monitor for exploitation attempts while awaiting a vendor patch
- Consider temporarily disabling the document processing functionality if not critical to operations
Patch Information
Consult the Hyland Alfresco Platform documentation and security advisories for official patch information. Monitor the VulnCheck Advisory for updates regarding available patches or mitigations.
Workarounds
- Deploy a reverse proxy in front of the Transformation Service with strict URL filtering and validation
- Implement network-level controls to block the Transformation Service from accessing internal IP ranges (RFC 1918) and cloud metadata endpoints
- Use a Web Application Firewall (WAF) to filter requests containing SSRF payloads
- Require authentication for access to the Transformation Service endpoints if possible
- Segment the Transformation Service into an isolated network zone with restricted outbound connectivity
# Example: iptables rules to block cloud metadata and internal network access
# Block cloud metadata endpoint
iptables -A OUTPUT -d 169.254.169.254 -j DROP
# Block internal network ranges from transformation service
iptables -A OUTPUT -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
