CVE-2026-7158 Overview
A Server-Side Request Forgery (SSRF) vulnerability has been identified in dmitryglhf mcp-url-downloader up to commit 4b8cf2de55f6e8864a77d108e8a94a5b8e4394c6. The vulnerability exists in the _validate_url_safe function within the src/mcp_url_downloader/server.py file. An attacker can manipulate the url argument to conduct SSRF attacks, potentially accessing internal services, bypassing security controls, or exfiltrating sensitive data from internal networks.
Critical Impact
Remote attackers can exploit this SSRF vulnerability to make the server send requests to arbitrary internal or external destinations, potentially exposing internal services, cloud metadata endpoints, or enabling further attacks against internal infrastructure.
Affected Products
- dmitryglhf mcp-url-downloader (up to commit 4b8cf2de55f6e8864a77d108e8a94a5b8e4394c6)
Discovery Timeline
- 2026-04-27 - CVE CVE-2026-7158 published to NVD
- 2026-04-29 - Last updated in NVD database
Technical Details for CVE-2026-7158
Vulnerability Analysis
This vulnerability is classified as CWE-918 (Server-Side Request Forgery). The _validate_url_safe function in server.py fails to adequately validate and sanitize user-supplied URL inputs before processing them. This allows attackers to craft malicious URLs that cause the server to make unintended requests to internal or external resources.
SSRF vulnerabilities are particularly dangerous in cloud environments where attackers can target cloud metadata services (such as AWS EC2 metadata at 169.254.169.254) to extract credentials, tokens, or sensitive configuration data. The network-accessible nature of this vulnerability means exploitation can occur remotely without authentication.
The project implements a rolling release model, which means specific version numbers for affected or patched releases are unavailable. The vulnerability has been publicly disclosed via a GitHub Issue Discussion, but the project maintainers have not yet responded to the report.
Root Cause
The root cause lies in insufficient URL validation within the _validate_url_safe function. The function does not properly restrict which URLs can be requested, failing to block requests to internal IP ranges, localhost, cloud metadata endpoints, or other sensitive destinations. This inadequate input validation allows attackers to bypass intended URL restrictions and access protected resources.
Attack Vector
The attack vector is network-based and can be executed remotely. An attacker supplies a malicious URL to the application, which then processes the URL through the vulnerable _validate_url_safe function. Due to insufficient validation, the server makes a request to the attacker-controlled destination, which could be an internal service, cloud metadata endpoint, or other restricted resource.
Typical attack scenarios include:
- Accessing cloud provider metadata services to steal credentials
- Scanning internal network infrastructure
- Accessing internal APIs or administrative interfaces
- Bypassing firewall rules by using the server as a proxy
Detection Methods for CVE-2026-7158
Indicators of Compromise
- Unexpected outbound requests from the mcp-url-downloader server to internal IP ranges (e.g., 10.x.x.x, 192.168.x.x, 172.16.x.x)
- Requests to cloud metadata endpoints such as 169.254.169.254 or fd00:ec2::254
- Unusual URL patterns in application logs containing localhost references or internal hostnames
- Outbound connections to unexpected external services initiated by the server process
Detection Strategies
- Monitor network traffic for requests from the mcp-url-downloader service to internal IP addresses or metadata endpoints
- Implement web application firewall (WAF) rules to detect SSRF attack patterns in URL parameters
- Review application logs for URL patterns containing internal IP addresses, localhost, or cloud metadata URLs
- Deploy network segmentation monitoring to detect unauthorized cross-zone traffic
Monitoring Recommendations
- Enable detailed logging for all URL download requests and their destinations
- Configure alerts for any requests targeting private IP ranges or metadata endpoints
- Monitor for abnormal request patterns such as sequential scanning of internal IPs
- Implement egress filtering and log all blocked outbound connection attempts
How to Mitigate CVE-2026-7158
Immediate Actions Required
- Restrict network access to the mcp-url-downloader service using firewall rules
- Implement egress filtering to prevent requests to internal networks and cloud metadata endpoints
- Review and audit existing deployments for signs of exploitation
- Consider disabling the service until a patch is available
Patch Information
No official patch is currently available. The project maintains a rolling release model without specific version numbers. The GitHub Issue Discussion documents the vulnerability disclosure, but the project maintainers have not yet responded. Users should monitor the repository for updates and apply any fixes when they become available.
Workarounds
- Implement a URL allowlist that restricts which domains and IP ranges can be requested
- Deploy network-level controls to block outbound requests to internal IP ranges and cloud metadata endpoints from the server
- Use a web proxy with strict URL filtering between the mcp-url-downloader service and external networks
- Consider running the service in an isolated network segment with restricted egress capabilities
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
