GuardDog SSRF and GH_TOKEN Exfiltration via Blind URL Rewrite (CVE-2026-44971)

GuardDog, a dependency analysis tool, is vulnerable to Server-Side Request Forgery (SSRF) due to a flaw in its remote project scanning functionality. Specifically, versions 1.0.0 through 2.9.0 are affected. The vulnerability arises from the ProjectScanner.scan_remote() function, which blindly rewrites URLs without proper validation. By crafting a malicious URL that includes an attacker-controlled hostname, an attacker can redirect requests to an arbitrary server. This includes the potential for the GuardDog instance to send its configured GitHub credentials (GH_TOKEN) via HTTP Basic Authentication to the attacker’s server. This vulnerability allows attackers to steal GitHub PATs, perform SSRF against internal services, and control the content of dependency files. This issue was assigned CVE-2026-44971.

Attack Chain

1. The attacker identifies a GuardDog instance scanning a repository URL they can influence.
2. The attacker crafts a malicious repository URL, embedding an attacker-controlled hostname (e.g., http://github@127.0.0.1:18081/owner/repo).
3. GuardDog’s ProjectScanner.scan_remote() function receives the attacker-controlled URL.
4. The scan_remote() function performs a blind string replacement, transforming “github” to “raw.githubusercontent”, resulting in a URL like http://raw.githubusercontent@127.0.0.1:18081/owner/repo/main/requirements.txt.
5. The requests.get() function interprets the URL as a request to 127.0.0.1:18081.
6. GuardDog includes the configured GH_TOKEN as HTTP Basic Authentication credentials in the request’s Authorization header.
7. The attacker’s server receives the request, logging the Authorization header and requested path.
8. The attacker extracts the GH_TOKEN from the captured Authorization header or influences the dependency file content.

Impact

Successful exploitation can lead to several critical consequences. The primary risk is the theft of the GitHub Personal Access Token (PAT) configured in the GH_TOKEN environment variable, allowing the attacker to impersonate the GuardDog instance and access its GitHub resources. Additionally, the SSRF vulnerability enables attacks against internal or localhost services reachable by the scanner, potentially compromising sensitive internal systems. Finally, the attacker can control the content of dependency files, leading to supply chain attacks.

Recommendation

• Deploy the Sigma rule Detect GuardDog GH_TOKEN Exfiltration Attempt to identify potential exfiltration attempts by monitoring network connections to non-GitHub hosts using the GitHub token.
• Apply the suggested fix outlined in the advisory: parse the input URL, require hostname == "github.com", validate the path shape, build the raw URL from parsed components instead of string replacement, and never send GitHub credentials to non-GitHub hosts.
• Upgrade GuardDog to a version beyond 2.9.0 to remediate CVE-2026-44971.