CVE-2025-61152

python-jose thru 3.3.0 allows JWT tokens with 'alg=none' to be decoded and accepted without any cryptographic signature verification. A malicious actor can craft a forged token with arbitrary claims (e.g., is_admin=true) and bypass authentication checks, leading to privilege escalation or unauthorized access in applications that rely on python-jose for token validation. This issue is exploitable unless developers explicitly reject 'alg=none' tokens, which is not enforced by the library. NOTE: all parties agree that the issue is not relevant because it only occurs in a "verify_signature": False situation.

CVSS v3.1

6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

0.30% chance of exploitation in the next 30 days, 23th percentile

Published

2025-10-10

Updated

2025-11-25

Proof-of-concept exploits (1)

• javiermorales36/PoC-for-python-jose-alg-none-JWT-bypass-vulnerability

References

• CVE Record
• NVD entry

Related

• CVE-2025-6115
• CVE-2025-6116
• CVE-2025-6114
• CVE-2025-6117
• CVE-2025-6113
• CVE-2025-6118