CVE-2026-0932 Overview
A blind server-side request forgery (SSRF) vulnerability exists in the legacy connection methods of document co-authoring features in M-Files Server versions prior to 26.3. This vulnerability allows an unauthenticated attacker to manipulate the server into sending HTTP GET requests to arbitrary URLs, potentially enabling reconnaissance of internal networks, access to internal services, or abuse of cloud metadata services.
Critical Impact
Unauthenticated attackers can leverage this SSRF vulnerability to force M-Files Server to make arbitrary outbound HTTP requests, potentially exposing internal network resources and sensitive metadata endpoints.
Affected Products
- M-Files Server versions before 26.3
- M-Files M-files Server (all affected builds prior to the patch)
- Legacy document co-authoring feature components
Discovery Timeline
- April 1, 2026 - CVE-2026-0932 published to NVD
- April 2, 2026 - Last updated in NVD database
Technical Details for CVE-2026-0932
Vulnerability Analysis
This blind SSRF vulnerability (CWE-918) exists within the legacy connection methods used by M-Files Server's document co-authoring functionality. The vulnerability is categorized as network-accessible, meaning attackers can exploit it remotely without requiring authentication or user interaction. The flaw allows limited confidentiality and availability impact, as the server can be coerced into making outbound requests that may leak information about internal infrastructure or cause resource consumption.
The blind nature of this SSRF means that while the attacker can trigger outbound requests, they typically cannot directly view the response content. However, this still presents significant security concerns as it can be used for port scanning internal networks, accessing cloud provider metadata services (such as AWS IMDSv1), or pivoting to attack internal services that trust requests from the M-Files Server's IP address.
Root Cause
The root cause lies in insufficient validation of URLs within the legacy connection methods of the document co-authoring feature. When processing co-authoring requests, the server fails to properly sanitize or restrict the target URLs, allowing arbitrary destinations to be specified. This lack of input validation enables attackers to redirect server-side requests to unintended endpoints.
Attack Vector
The attack vector is network-based and requires no authentication or privileges. An attacker can craft malicious requests to the vulnerable co-authoring endpoints, specifying arbitrary URLs as connection targets. The M-Files Server then initiates HTTP GET requests to these attacker-controlled destinations on behalf of the server.
Potential exploitation scenarios include:
- Internal network reconnaissance: Scanning internal IP ranges and ports to map network topology
- Cloud metadata service access: Targeting cloud provider metadata endpoints (e.g., http://169.254.169.254/) to retrieve instance credentials
- Internal service interaction: Accessing internal APIs or services that trust requests from the server's IP
- Data exfiltration via DNS: Using DNS-based exfiltration techniques to leak internal data
Detection Methods for CVE-2026-0932
Indicators of Compromise
- Unusual outbound HTTP GET requests originating from M-Files Server to unexpected internal IP ranges
- Requests to cloud metadata service endpoints (169.254.169.254) from the M-Files Server
- Anomalous DNS queries or HTTP connections to external domains not part of normal operations
- High volume of connection attempts to various internal ports from the M-Files Server process
Detection Strategies
- Monitor M-Files Server outbound network traffic for requests to internal RFC 1918 IP ranges (10.x.x.x, 172.16-31.x.x, 192.168.x.x)
- Implement detection rules for cloud metadata endpoint access attempts from application servers
- Review M-Files Server logs for unusual co-authoring feature activity or connection errors
- Deploy network segmentation monitoring to detect lateral movement attempts
Monitoring Recommendations
- Enable verbose logging on M-Files Server for document co-authoring operations
- Configure firewall logging to capture all outbound connections from the M-Files Server
- Implement egress filtering with logging to detect unauthorized outbound request patterns
- Set up alerts for requests to known sensitive internal endpoints or metadata services
How to Mitigate CVE-2026-0932
Immediate Actions Required
- Upgrade M-Files Server to version 26.3 or later immediately
- If immediate patching is not possible, disable or restrict access to legacy document co-authoring features
- Implement strict egress filtering to limit outbound connections from the M-Files Server
- Block access to cloud metadata endpoints from application servers at the network level
Patch Information
M-Files has released version 26.3 which addresses this SSRF vulnerability. Organizations should consult the official M-Files Security Advisory for detailed upgrade instructions and release notes. Additional information is available through the M-Files Empower Portal Security Advisory.
Workarounds
- Disable legacy co-authoring connection methods if they are not required for business operations
- Implement network-level controls to restrict M-Files Server outbound connectivity to only necessary destinations
- Deploy a web application firewall (WAF) or reverse proxy that can filter suspicious requests to co-authoring endpoints
- Use network segmentation to isolate M-Files Server from sensitive internal resources
# Example: Block cloud metadata endpoint access from application servers (iptables)
# Apply to M-Files Server to prevent SSRF to cloud metadata services
iptables -A OUTPUT -d 169.254.169.254 -j DROP
iptables -A OUTPUT -d 169.254.169.254 -j LOG --log-prefix "SSRF_ATTEMPT: "
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
