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The vulnerability stems from a flaw in OpenLearnX’s JSON Web Token (JWT) implementation. Specifically, the JWT signature verification process is disabled or can be bypassed, allowing an attacker to forge valid authentication tokens. This is often due to the server accepting tokens with the `alg` header set to `none` or failing to enforce the use of a strong signing algorithm. When the `none` algorithm is permitted, the token’s signature component is ignored, making it trivial to alter the payload (which contains user identity and claims). An attacker can craft a new JWT by modifying the payload fields (e.g., user, role, sub) to impersonate another user or escalate privileges. The token is then sent to the server, which, due to the flawed verification, accepts it as legitimate. This allows the attacker to bypass authentication entirely, leading to full account takeover and unauthorized access to the victim’s data and functions within the OpenLearnX platform.
DailyCVE Form
Platform: OpenLearnX
Version: <2.0.3
Vulnerability: Auth Bypass
Severity: Moderate
date: 2026-05-13
Prediction: 2026-05-20
Analytics under What Undercode Say:
Simulated log analysis for JWT none-algorithm usage grep -i "jwt" /var/log/openlearnx/auth.log | grep "alg: none"
Python code to generate a malicious JWT with 'none' algorithm
import jwt
Original token payload
payload = {"user": "attacker", "role": "admin"}
Create token with 'none' algorithm - no signature check
malicious_token = jwt.encode(payload, key="", algorithm="none")
print(f"Malicious Token: {malicious_token}")
Exploit:
- Intercept a valid JWT issued by OpenLearnX to a low-privileged user.
- Decode the JWT payload and modify critical claims (e.g.,
"user": "victim", "role": "admin"). - Change the `alg` header in the JWT to
none. - Remove the signature part of the token (or set it to an empty string).
- Replay the crafted token in an HTTP request to an authenticated endpoint (e.g.,
/api/user/profile). - Due to the disabled signature verification, the server accepts the forged token and grants access as the victim/admin.
Protection from this CVE:
Upgrade OpenLearnX to the latest patched version (>2.0.3).
Enforce strict JWT algorithm validation: Reject any tokens with the `none` algorithm.
Implement robust signature verification for all incoming JWTs, ensuring the token has been signed with the expected secret or public key.
Use JWT libraries with secure defaults (e.g., those that do not support the `none` algorithm).
Impact:
Account Takeover: Attackers can impersonate any user, including administrators.
Data Breach: Unauthorized access to sensitive user data, course materials, and assessment results.
Privilege Escalation: Low-privileged users can elevate their roles to perform administrative actions.
Reputational Damage: Compromise of the platform’s integrity leads to loss of user trust.
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Sources:
Reported By: github.com
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