CVE-2026-30840: Wallosapp Wallos SSRF Vulnerability

CVE-2026-30840 Overview

CVE-2026-30840 is a Server-Side Request Forgery (SSRF) vulnerability affecting Wallos, an open-source, self-hostable personal subscription tracker application. The vulnerability exists in the notification testers functionality and allows authenticated attackers to force the server to make arbitrary HTTP requests to internal or external resources. This can lead to unauthorized access to internal services, information disclosure, and potential lateral movement within network infrastructure.

Critical Impact

Authenticated attackers can exploit the SSRF vulnerability in notification testers to access internal network resources, exfiltrate sensitive data, and potentially pivot to attack other internal systems that would otherwise be inaccessible from external networks.

Affected Products

• Wallos versions prior to 4.6.2
• Self-hosted Wallos deployments with notification testing features enabled
• Wallosapp Wallos (all platforms)

Discovery Timeline

• 2026-03-07 - CVE CVE-2026-30840 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-30840

Vulnerability Analysis

The SSRF vulnerability resides in the notification testing functionality of Wallos. When users configure notification services (such as webhooks or external notification providers), the application provides a testing feature to verify connectivity. This testing mechanism fails to properly validate and restrict the URLs that can be requested, allowing attackers to craft malicious requests that target internal network resources.

The vulnerability is classified under CWE-295 (Improper Certificate Validation), which indicates that the application does not properly validate certificates when making outbound requests. This allows attackers to bypass security controls and potentially intercept or manipulate traffic. The network-based attack vector with low complexity makes this vulnerability particularly concerning for organizations running self-hosted Wallos instances within their internal networks.

An attacker with low-privilege authenticated access can abuse this functionality to probe internal network infrastructure, access cloud metadata services, interact with internal APIs, or retrieve sensitive configuration data from services that trust requests originating from the Wallos server.

Root Cause

The root cause of this vulnerability is improper input validation and URL scheme restriction in the notification testing code path. The application accepts user-controlled URL inputs for notification service testing without adequate validation of the destination address. This allows attackers to specify URLs pointing to:

• Internal IP addresses (e.g., 127.0.0.1, 10.x.x.x, 192.168.x.x)
• Cloud provider metadata endpoints (e.g., 169.254.169.254)
• Internal hostnames and services
• Local file system resources via file:// protocol (if supported)

Additionally, the improper certificate validation (CWE-295) compounds the issue by allowing the application to connect to endpoints with invalid or self-signed certificates without proper verification.

Attack Vector

The attack vector is network-based and requires authenticated access to the Wallos application. An attacker can exploit this vulnerability through the following attack flow:

1. Authenticate to the Wallos application with valid credentials (even low-privilege accounts)
2. Navigate to the notification settings or testing functionality
3. Configure a notification endpoint pointing to an internal resource or sensitive endpoint
4. Trigger the notification test feature
5. The server makes the request on behalf of the attacker, potentially returning sensitive information or allowing interaction with internal services

Since the Wallos server acts as a proxy for these requests, the attacker can bypass network security controls that would normally prevent direct access to internal resources. For detailed technical information, refer to the GitHub Security Advisory GHSA-mr2c-prqv-hqm8.

Detection Methods for CVE-2026-30840

Indicators of Compromise

• Unusual outbound HTTP requests from the Wallos server to internal IP ranges
• Requests to cloud metadata endpoints (e.g., 169.254.169.254) from the Wallos application
• Notification test requests containing internal hostnames or non-routable IP addresses
• Increased frequency of notification testing activities from specific user accounts
• Log entries showing requests to unexpected internal services or ports

Detection Strategies

• Monitor application logs for notification test requests targeting internal IP ranges or localhost
• Implement network detection rules to alert on requests from the Wallos server to sensitive internal endpoints
• Review access logs for patterns of notification testing followed by access to unusual resources
• Deploy web application firewall (WAF) rules to detect SSRF payload patterns in request parameters

Monitoring Recommendations

• Enable detailed logging for all notification testing functionality within Wallos
• Configure network monitoring to track outbound requests from web application servers
• Implement alerting for any requests to cloud metadata services from application servers
• Regularly audit user activity related to notification configuration changes

How to Mitigate CVE-2026-30840

Immediate Actions Required

• Upgrade Wallos to version 4.6.2 or later immediately
• Review notification configurations for any suspicious or unexpected URLs
• Audit access logs for signs of exploitation attempts
• Implement network segmentation to limit the impact of potential SSRF attacks
• Restrict outbound network access from Wallos servers to only necessary destinations

Patch Information

The vulnerability has been patched in Wallos version 4.6.2. The fix implements proper URL validation and restrictions to prevent SSRF attacks through the notification testing functionality. Users should update their Wallos installations immediately by pulling the latest version from the official repository.

For detailed patch information, refer to the official security fix commit and the release notes for version 4.6.2.

Workarounds

• Implement network-level controls to block outbound requests from the Wallos server to internal IP ranges
• Disable notification testing functionality if not required until the patch can be applied
• Use a reverse proxy to filter and validate outbound requests from the application
• Restrict user access to notification configuration features to trusted administrators only

# Example: Docker container network isolation for Wallos
# Create an isolated network with restricted internal access
docker network create --driver bridge \
  --opt com.docker.network.bridge.enable_ip_masquerade=true \
  --subnet=172.20.0.0/16 \
  wallos-isolated

# Run Wallos with restricted network access
docker run -d \
  --name wallos \
  --network wallos-isolated \
  -p 8080:80 \
  wallosapp/wallos:4.6.2