CVE-2026-25870: DoraCMS UEditor SSRF Vulnerability

CVE-2026-25870 Overview

DoraCMS version 3.1 and prior contains a server-side request forgery (SSRF) vulnerability in its UEditor remote image fetch functionality. The application accepts user-supplied URLs and performs server-side HTTP or HTTPS requests without sufficient validation or destination restrictions. The implementation does not enforce allowlists, block internal or private IP address ranges, or apply request timeouts or response size limits. An attacker can abuse this behavior to induce the server to issue outbound requests to arbitrary hosts, including internal network resources, potentially enabling internal network scanning and denial of service through resource exhaustion.

Critical Impact

Attackers can leverage this SSRF vulnerability to scan internal networks, access internal services, and potentially cause denial of service through resource exhaustion on the DoraCMS server.

Affected Products

• DoraCMS version 3.1
• DoraCMS versions prior to 3.1
• DoraCMS UEditor component with remote image fetch functionality

Discovery Timeline

• 2026-02-10 - CVE-2026-25870 published to NVD
• 2026-02-11 - Last updated in NVD database

Technical Details for CVE-2026-25870

Vulnerability Analysis

This vulnerability is classified as CWE-918 (Server-Side Request Forgery). The UEditor component in DoraCMS includes a remote image fetch feature that allows users to specify URLs for images to be retrieved by the server. The server-side implementation fails to properly validate or restrict the destination of these requests, creating a classic SSRF attack surface.

The vulnerable functionality processes user-supplied URLs without implementing critical security controls such as URL allowlisting, IP address range blocking for internal/private networks (RFC 1918 addresses), DNS rebinding protections, request timeouts, or response size limits. This permissive configuration allows attackers to craft malicious requests that cause the server to communicate with arbitrary internal or external endpoints.

Root Cause

The root cause of this vulnerability lies in the insufficient input validation within the UEditor remote image fetch functionality. The application trusts user-supplied URL input without implementing proper security controls. Specifically, the implementation lacks:

• URL scheme validation (allowing http://, https://, and potentially other protocols)
• Hostname/IP address allowlisting or blocklisting
• Rejection of private IP address ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 127.0.0.0/8)
• Protection against DNS rebinding attacks
• Request timeout enforcement
• Response size limits to prevent resource exhaustion

Attack Vector

The attack vector is network-based and does not require authentication. An attacker exploits this vulnerability by submitting crafted requests to the UEditor remote image fetch endpoint with malicious URLs pointing to internal network resources or external attacker-controlled servers.

The vulnerability can be exploited through the remote image fetch API endpoint by providing a URL parameter that points to internal services. For example, an attacker could target internal metadata services, administrative interfaces, or other internal network resources that would otherwise be inaccessible from external networks. The server then acts as a proxy, making requests on behalf of the attacker and potentially returning sensitive information or enabling further reconnaissance of the internal network. For detailed technical information, refer to the VulnCheck Advisory and the GitHub Issue #268.

Detection Methods for CVE-2026-25870

Indicators of Compromise

• Unusual outbound HTTP/HTTPS requests from the DoraCMS server to internal IP addresses or unexpected external hosts
• Requests to cloud metadata endpoints (e.g., 169.254.169.254) originating from the application server
• High volume of requests to the UEditor remote image fetch endpoint with varying URL parameters
• Error logs indicating connection attempts to internal services or blocked IP ranges

Detection Strategies

• Implement network monitoring to detect outbound connections from the DoraCMS server to internal network ranges or sensitive endpoints
• Deploy web application firewall (WAF) rules to detect and block SSRF patterns in URL parameters
• Monitor application logs for unusual URL patterns in the UEditor image fetch functionality
• Use SentinelOne Singularity to detect anomalous network behavior from the application process

Monitoring Recommendations

• Enable verbose logging for all outbound HTTP requests made by the DoraCMS application
• Configure alerts for outbound connections to RFC 1918 private address ranges from the web server
• Monitor DNS queries from the DoraCMS server for internal hostnames or suspicious domains
• Implement egress filtering and monitor for policy violations

How to Mitigate CVE-2026-25870

Immediate Actions Required

• Review and restrict the UEditor remote image fetch functionality if not required for business operations
• Implement network-level egress filtering to block outbound requests to internal IP ranges from the DoraCMS server
• Deploy a web application firewall with SSRF protection rules in front of the DoraCMS application
• Monitor for exploitation attempts while awaiting an official patch

Patch Information

As of the last NVD update on 2026-02-11, no official patch has been released. Organizations should monitor the DoraCMS Official Website and GitHub repository for security updates. Contact the vendor directly for remediation guidance.

Workarounds

• Disable the UEditor remote image fetch functionality if it is not a required feature
• Implement application-level URL validation with a strict allowlist of permitted domains
• Configure network-level controls to prevent the DoraCMS server from making requests to internal IP ranges
• Use a reverse proxy or WAF to filter and validate URLs before they reach the application

# Example: iptables rules to block outbound requests to private IP ranges from web server
# Block requests to 10.0.0.0/8
iptables -A OUTPUT -m owner --uid-owner www-data -d 10.0.0.0/8 -j DROP
# Block requests to 172.16.0.0/12
iptables -A OUTPUT -m owner --uid-owner www-data -d 172.16.0.0/12 -j DROP
# Block requests to 192.168.0.0/16
iptables -A OUTPUT -m owner --uid-owner www-data -d 192.168.0.0/16 -j DROP
# Block requests to localhost
iptables -A OUTPUT -m owner --uid-owner www-data -d 127.0.0.0/8 -j DROP
# Block requests to link-local (cloud metadata)
iptables -A OUTPUT -m owner --uid-owner www-data -d 169.254.0.0/16 -j DROP