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The vulnerability (CVE-2025-XXXX) in Payload CMS stems from an insecure JWT logout implementation. During authentication, the server issues a JWT containing a payload (e.g., user ID, roles) and a cryptographic signature. This token is stateless; the server validates API requests by verifying the token’s signature and expiration timestamp, not by checking a central revocation list. The flaw occurs when a user logs out. The client-side application may discard the token, but the server performs no action to invalidate it. Since the JWT remains cryptographically valid until its natural expiration, any previously issued token can be reused for unauthorized API access. An attacker in possession of a stolen token can impersonate the victim indefinitely until the token’s expiry, bypassing authentication and gaining access to the user’s privileges and data without needing valid credentials.
Platform: Payload CMS
Version: <3.44.0
Vulnerability: Auth Bypass
Severity: Moderate
date: 2025-08-29
Prediction: Patch: 2025-08-29
What Undercode Say:
Check JWT expiration from command line
echo "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyLCJleHAiOjE2MzAwMDAwMDB9.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c" | awk -F. '{print $2}' | base64 -d 2>/dev/null | jq '.exp'
Curl with a potentially stolen JWT
curl -H "Authorization: Bearer <STOLEN_JWT>" http://vulnerable-site.com/api/user/data
How Exploit:
An attacker captures a JWT via MitM, browser storage extraction, or log leakage. They then use this token in API request headers to impersonate the victim user, accessing privileged endpoints and data until the token expires.
Protection from this CVE:
Upgrade to Payload CMS version 3.44.0 immediately. Implement server-side token blacklisting upon logout or utilize short-lived tokens with refresh rotation.
Impact:
Authentication Bypass, unauthorized data access, privilege escalation, and account takeover for the token’s lifetime.
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Sources:
Reported By: github.com
Extra Source Hub:
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