CVE-2025-46651: Tiny File Manager SSRF Vulnerability

CVE-2025-46651 Overview

CVE-2025-46651 is a Server-Side Request Forgery (SSRF) vulnerability affecting Tiny File Manager through version 2.6. The vulnerability exists in the URL upload feature due to insufficient validation of user-supplied URLs. An attacker with low privileges can exploit this flaw to send crafted requests to localhost using specially constructed domain names such as http://www.127.0.0.1.example.com/ or similar bypass techniques. This may lead to unauthorized port scanning or access to internal-only services that should not be accessible from external networks.

Critical Impact

Authenticated attackers can leverage the SSRF vulnerability to probe internal network services, potentially discovering sensitive endpoints, performing port scans on localhost, or accessing internal APIs that are not exposed to the public internet.

Affected Products

• Tiny File Manager through version 2.6
• Tiny File Manager installations with URL upload feature enabled
• Web servers hosting Tiny File Manager with access to internal network resources

Discovery Timeline

• 2026-02-03 - CVE-2025-46651 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2025-46651

Vulnerability Analysis

This SSRF vulnerability (CWE-918) stems from inadequate URL validation in Tiny File Manager's URL upload functionality. The application fails to properly sanitize and validate user-supplied URLs before making server-side HTTP requests. The root cause lies in the insufficient blocklist-based approach to URL filtering, which can be trivially bypassed using DNS rebinding techniques or specially crafted domain names that resolve to internal IP addresses.

When a user submits a URL for upload, the application parses and attempts to fetch content from that URL. However, the validation logic does not account for creative DNS-based bypasses. An attacker can register a domain like www.127.0.0.1.example.com that resolves to 127.0.0.1, effectively tricking the application into making requests to localhost or other internal network addresses.

The vulnerability requires low-level authentication to exploit, as the URL upload feature is typically available to authenticated users. The attack can be executed over the network without any user interaction.

Root Cause

The vulnerability originates from improper input validation in the URL upload handling code within tinyfilemanager.php. The application uses an insufficient validation mechanism that checks for obvious localhost patterns but fails to account for DNS-based bypasses. The vulnerable code is located around line 608 of the tinyfilemanager.php file. Proper SSRF mitigation requires validating the resolved IP address after DNS resolution, not just the textual URL pattern.

Attack Vector

The attack is network-based and requires an authenticated user account. An attacker with valid credentials can navigate to the URL upload feature and submit a malicious URL designed to bypass the hostname validation. By crafting a domain name that appears legitimate but resolves to internal addresses (such as 127.0.0.1, 169.254.x.x, 10.x.x.x, 192.168.x.x, or 172.16-31.x.x), the attacker forces the server to make requests to internal services.

Example bypass techniques include:

• Using subdomains that resolve to localhost: 127.0.0.1.attacker.com
• IPv6 representations: ::1 or 0:0:0:0:0:0:0:1
• Decimal IP notation: http://2130706433/ (decimal for 127.0.0.1)
• URL encoding variations and mixed case bypasses

For detailed technical information about this vulnerability, refer to the GitHub Security Advisory for CVE-2025-46651.

Detection Methods for CVE-2025-46651

Indicators of Compromise

• Unusual outbound HTTP requests from the web server to internal IP ranges (127.0.0.1, 10.x.x.x, 192.168.x.x, 172.16-31.x.x)
• Access logs showing URL upload requests with suspicious domain names containing IP address patterns
• Web server making unexpected connections to local services on non-standard ports
• DNS queries from the web server for domains with embedded IP addresses or unusual subdomains

Detection Strategies

• Implement web application firewall (WAF) rules to detect SSRF patterns in URL upload parameters
• Monitor outbound network connections from web servers for attempts to reach internal addresses
• Review Tiny File Manager access logs for upload requests containing suspicious URL patterns like 127.0.0.1, localhost, or encoded IP addresses
• Deploy network segmentation monitoring to detect unexpected cross-segment communication from web application servers

Monitoring Recommendations

• Configure SIEM alerts for outbound connections from web servers to RFC1918 private address ranges
• Enable verbose logging on Tiny File Manager to capture all URL upload attempts with full request details
• Implement DNS query logging to identify resolution requests for suspicious domain patterns
• Set up network flow monitoring to detect port scanning behavior originating from the web server

How to Mitigate CVE-2025-46651

Immediate Actions Required

• Disable the URL upload feature in Tiny File Manager if not strictly required for business operations
• Implement network-level restrictions to prevent the web server from accessing internal services
• Apply IP-based egress filtering to limit outbound connections from the web application server
• Review and audit all user accounts with access to the URL upload functionality

Patch Information

As of the last NVD update on 2026-02-05, users should check the official Tiny File Manager GitHub repository for security updates and patches addressing this vulnerability. Monitor the security advisory for updates on available fixes.

Workarounds

• Disable URL upload functionality by modifying the Tiny File Manager configuration to prevent remote URL fetching
• Implement a reverse proxy or WAF in front of Tiny File Manager with SSRF-specific filtering rules
• Configure firewall rules to restrict outbound connections from the web server to only necessary external services
• Use network segmentation to isolate the web server from sensitive internal services and networks

# Example iptables rules to restrict outbound connections from web server
# Block connections to private IP ranges from web server process
iptables -A OUTPUT -m owner --uid-owner www-data -d 127.0.0.0/8 -j DROP
iptables -A OUTPUT -m owner --uid-owner www-data -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -m owner --uid-owner www-data -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -m owner --uid-owner www-data -d 192.168.0.0/16 -j DROP
iptables -A OUTPUT -m owner --uid-owner www-data -d 169.254.0.0/16 -j DROP