Summary
TsDProxy: X-Forwarded-For header injection allows IP spoofing in proxied requests to backend services
Impact
An authenticated Tailscale user who should only have regular user access can:
- Bypass IP-based admin restrictions on the backend application by spoofing X-Forwarded-For to 127.0.0.1
- Appear as any arbitrary IP address in audit logs
- Bypass rate limiting tied to source IP
- Bypass geo-blocking or network-segment restrictions enforced by the backend
This is especially impactful because tsdproxy is designed as the sole access point for backend services that are otherwise network-isolated -- making the proxy the only enforcement boundary.
Fix: Add r.Out.Header.Del("X-Forwarded-For") and r.Out.Header.Del("X-Real-IP") in the Rewrite closure before calling r.SetXForwarded(). This ensures only the real Tailscale client IP appears in the XFF chain.
GHSA-PQG7-V6WH-3PFP has a CVSS score of 8.5 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-PQG7-V6WH-3PFP? GHSA-PQG7-V6WH-3PFP is a high-severity security vulnerability in github.com/almeidapaulopt/tsdproxy (go), affecting versions < 3.0.0-alpha.3. No fixed version is listed yet.
- How severe is GHSA-PQG7-V6WH-3PFP? GHSA-PQG7-V6WH-3PFP has a CVSS score of 8.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/almeidapaulopt/tsdproxy are affected by GHSA-PQG7-V6WH-3PFP? github.com/almeidapaulopt/tsdproxy (go) versions < 3.0.0-alpha.3 is affected.
- Is there a fix for GHSA-PQG7-V6WH-3PFP? No fixed version is listed for GHSA-PQG7-V6WH-3PFP yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is GHSA-PQG7-V6WH-3PFP exploitable, and should I be worried? Whether GHSA-PQG7-V6WH-3PFP is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-PQG7-V6WH-3PFP is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.