CVE-2025-61152

Published Oct 10, 2025

Last updated 11 days ago

CVSS medium 6.5
Jwt

Overview

Description
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.
Source
cve@mitre.org
NVD status
Deferred
CNA Tags
disputed

Risk scores

CVSS 3.1

Type
Secondary
Base score
6.5
Impact score
2.5
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Severity
MEDIUM

Weaknesses

134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-269

Social media

Hype score
Not currently trending

  1. 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 fo… https://t.co/HZ6ccni5lK

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    10 Oct 2025

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References

Sources include official advisories and independent security research.