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The vulnerability arises due to flawed permission evaluation logic in pyLoad’s API layer, specifically involving the `Perms.ANY` decorator flag. Because `Perms.ANY` is evaluated as integer zero, the bitwise AND operation performed during permission checks becomes a complete no-op for any authenticated principal. As a result, sensitive legacy API methods such as `getUserData` and get_userdata, which wrap around check_auth(), inadvertently bypass the intended administrator-only restrictions. An attacker holding the lowest-privileged user account with zero permission bits can exploit this flaw to query user authentication statuses. Combined with the absence of account lockout mechanisms and easily bypassable rate limits via manipulated request headers, malicious actors can perform high-speed online brute-force attacks against administrative credentials, ultimately achieving total administrative takeover of the application.
DailyCVE Form:
Platform: pyLoad
Version: 0.5.0b3.dev101
Vulnerability : Authentication Bypass
Severity: Critical
date: 2026-04-20
Prediction: 2026-04-30
What Undercode Say:
This vulnerability highlights a critical design flaw where sentinel permission flags interact incorrectly with bitwise validation logic, effectively turning security gates into open doors for authenticated low-privileged users.
Bash Commands and Codes:
curl -s "http://localhost:8000/api/getUserData?username=pyload&password=WRONG" curl -s "http://localhost:8000/api/getUserData?username=pyload&password=pyload"
Exploit (Educational Purposes!):
An authenticated low-privileged user leverages the unmasked `getUserData` or `get_userdata` endpoints as a binary oracle. By sending continuous HTTP requests with sequentially rotated `X-Forwarded-For` headers to bypass rate limits, the attacker brute-forces the administrator password without triggering any account lockouts, successfully recovering credentials and dumping all user details.
Protection:
Remove `@permission(Perms.ANY)` from legacy wrappers or drop them entirely.
Assign a distinct non-zero bit value to `Perms.ANY` or explicitly handle authentication checks.
Prevent `X-Forwarded-For` header spoofing unless behind a trusted proxy.
Implement strict per-account failed-authentication throttling and account lockouts.
Impact:
Full administrative account compromise, exposure of internal database user roles, permission structures, and complete control over the underlying download manager instance.
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Sources:
Reported By: github.com
Extra Source Hub:
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