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pyLoad contains a security vulnerability in its Web UI request-handling components where client-IP derivation relies unsafely on the client-supplied X-Forwarded-For HTTP header. Because the application lacks a trusted-proxy configuration and exposes its Cheroot WSGI server directly without a ProxyFix middleware, any external user can completely forge or rotate this header value on individual requests. Consequently, malicious clients can effortlessly bypass rate-limiting counters by creating distinct tracking buckets per request, while also poisoning audit logs with arbitrary fake source attribution IPs to evade detection mechanisms like fail2ban.
DailyCVE Form:
Platform: pyLoad
Version: 0.5.0b3
Vulnerability : IP Spoofing & Rate Limit Bypass
Severity: Medium
date: 2025-08-04
Prediction: 2025-08-15
What Undercode Say:
Analysis of the underlying code shows that the application extracts the client IP address using a naive string split operation on the HTTP header without validating whether the connection traverses a trusted intermediary. Because the application accepts the leftmost token of the X-Forwarded-For header directly as the peer identifier, attackers can inject arbitrary addresses to defeat security boundaries.
Bash Commands and Code
for i in $(seq 1 500); do curl -s -o /dev/null -H "X-API-Key: pl_1<valid-key>" \ -H "X-Forwarded-For: 10.0.0.$((RANDOM%255))" \ http://127.0.0.1:8000/api/get_server_version done
client_ip = flask.request.headers.get("X-Forwarded-For", "").split(",")[bash].strip() or flask.request.remote_addr
Exploit: (Educational Purposes!)
Attackers leverage this flaw by sending HTTP requests to protected endpoints while injecting randomized or spoofed values into the X-Forwarded-For header. Because the rate-limiting decorator keys its internal history dictionaries directly on this untrusted string value, changing the header per request ensures that request counters never reach the configured threshold, entirely disabling throttling behavior. Similarly, passing an arbitrary address during failed login attempts causes the audit logger to record a falsified origin.
Protection: from this CVE
To secure deployments, administrators should ensure pyLoad is placed behind a properly configured reverse proxy that strips client-supplied header injection attempts, or implement explicit trusted-proxy validation via framework middleware such as ProxyFix to rely strictly on validated connection peers rather than raw headers.
Impact
The vulnerability completely invalidates rate-limiting protection on sensitive API routes, permitting continuous resource abuse and unthrottled brute-forcing attacks. Furthermore, security audit logging becomes completely untrustworthy for forensic analysis or automated defense frameworks like fail2ban due to source IP attribution poisoning.
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Sources:
Reported By: github.com
Extra Source Hub:
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