CVE-2026-6625: Mogu Blog SSRF Vulnerability

CVE-2026-6625 Overview

A Server-Side Request Forgery (SSRF) vulnerability has been identified in moxi624 Mogu Blog v2 through version 5.2. The vulnerability affects the LocalFileServiceImpl.uploadPictureByUrl function within the Picture Storage Service component. This flaw allows remote attackers to manipulate server-side requests, potentially enabling access to internal resources, data exfiltration, or further network reconnaissance from the vulnerable server's perspective.

Critical Impact

Remote attackers can exploit this SSRF vulnerability to force the Mogu Blog server to make arbitrary HTTP requests to internal or external resources, potentially bypassing network security controls and accessing sensitive internal services.

Affected Products

• moxi624 Mogu Blog v2 up to version 5.2
• Picture Storage Service component (mogu_picture)
• LocalFileServiceImpl.java service implementation

Discovery Timeline

• 2026-04-20 - CVE-2026-6625 published to NVD
• 2026-04-22 - Last updated in NVD database

Technical Details for CVE-2026-6625

Vulnerability Analysis

This SSRF vulnerability (CWE-918) exists within the picture upload functionality of Mogu Blog's Picture Storage Service. The vulnerable function LocalFileServiceImpl.uploadPictureByUrl accepts a URL parameter intended for fetching and storing remote images. However, insufficient validation of the supplied URL allows attackers to craft malicious requests that the server will execute on their behalf.

The attack can be initiated remotely without authentication, making it particularly concerning for internet-facing Mogu Blog deployments. An attacker could leverage this vulnerability to probe internal network infrastructure, access cloud metadata endpoints, interact with internal services, or exfiltrate sensitive data through controlled external endpoints.

Root Cause

The root cause of this vulnerability lies in inadequate input validation within the uploadPictureByUrl function located at mogu_picture/src/main/java/com/moxi/mogublog/picture/service/impl/LocalFileServiceImpl.java. The function fails to properly sanitize and validate user-supplied URLs before making server-side HTTP requests, allowing attackers to specify arbitrary destinations including internal IP addresses, localhost references, and cloud metadata services.

Attack Vector

The vulnerability is exploitable via network-based attacks. An attacker can submit a crafted URL to the picture upload endpoint, causing the server to make requests to attacker-controlled destinations or internal resources. Common SSRF attack patterns that may be applicable include:

• Accessing cloud metadata endpoints (e.g., http://169.254.169.254/)
• Scanning internal network ports and services
• Interacting with internal APIs or administrative interfaces
• Bypassing firewall restrictions by using the server as a proxy

The exploit has been publicly disclosed, as documented in the GitHub Issue Tracker. The vendor was contacted about this vulnerability but did not respond.

Detection Methods for CVE-2026-6625

Indicators of Compromise

• Unusual outbound HTTP requests from the Mogu Blog server to internal IP ranges (10.x.x.x, 172.16.x.x-172.31.x.x, 192.168.x.x)
• Requests to cloud metadata endpoints (169.254.169.254) originating from the application server
• Picture upload requests containing URLs pointing to localhost, loopback addresses, or internal hostnames
• Unexpected connections to non-standard ports from the mogu_picture service

Detection Strategies

• Monitor web application logs for picture upload requests containing suspicious URL patterns (internal IPs, localhost, metadata endpoints)
• Implement network-level detection for outbound requests from the Mogu Blog server to RFC 1918 private address spaces
• Deploy web application firewall (WAF) rules to detect and block SSRF payload patterns in upload URL parameters
• Configure intrusion detection systems to alert on anomalous outbound connection patterns from the application tier

Monitoring Recommendations

• Enable verbose logging for the Picture Storage Service component to capture all uploadPictureByUrl function invocations
• Implement DNS query logging to detect potential DNS rebinding attacks or internal hostname resolution attempts
• Monitor egress traffic patterns from the Mogu Blog server for unusual destinations or data volumes
• Set up alerts for any connections from the application server to cloud provider metadata services

How to Mitigate CVE-2026-6625

Immediate Actions Required

• Disable or restrict access to the picture upload by URL functionality until a patch is available
• Implement network-level egress filtering to prevent the Mogu Blog server from making requests to internal networks and cloud metadata endpoints
• Deploy WAF rules to block requests containing internal IP addresses or localhost references in URL parameters
• Review application logs for evidence of prior exploitation attempts

Patch Information

At the time of publication, the vendor (moxi624) has not released an official patch for this vulnerability. The vendor was contacted about this disclosure but did not respond. Organizations should monitor the official Mogu Blog repository for security updates and consider implementing workarounds until a fix is available.

For additional technical details, refer to the VulDB Vulnerability Details.

Workarounds

• Implement a URL allowlist that restricts the uploadPictureByUrl function to only fetch images from trusted external domains
• Add server-side validation to reject URLs containing private IP ranges, localhost, loopback addresses, and cloud metadata endpoints
• Deploy network segmentation to isolate the Mogu Blog server from sensitive internal resources
• Consider disabling the remote URL upload feature entirely if not required for business operations

# Example network-level mitigation using iptables
# Block outbound requests to common SSRF targets from the application server

# Block requests to cloud metadata endpoint
iptables -A OUTPUT -d 169.254.169.254 -j DROP

# Block requests to private IP ranges
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

# Block localhost/loopback (if not needed)
iptables -A OUTPUT -d 127.0.0.0/8 -j DROP