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.
Published: 2025-10-10
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 25 Nov 2025 17:30:00 +0000

Type Values Removed Values Added
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. 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.
References

Fri, 10 Oct 2025 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-269
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 10 Oct 2025 14:00:00 +0000

Type Values Removed Values Added
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.
References

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2025-11-25T17:09:56.140Z

Reserved: 2025-09-26T00:00:00.000Z

Link: CVE-2025-61152

cve-icon Vulnrichment

Updated: 2025-10-10T14:22:35.748Z

cve-icon NVD

Status : Deferred

Published: 2025-10-10T14:15:43.360

Modified: 2026-04-15T00:35:42.020

Link: CVE-2025-61152

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses