PyJWT is a Python implementation of JSON Web Token standards. From 2.0.0a1 until 2.15.0, PyJWT PyJWKClient.get_signing_key_from_jwt is affected because payload parser catches ValueError but not RecursionError. This occurs when an attacker-controlled recursively nested payload reaches json.loads. As a result, documented PyJWT exception handling does not contain the failure. Consequently, an unauthenticated request can raise an exception that may produce an HTTP 500 response. The advisory-defined affected implementation also includes jwt/api_jwt.py, verify_signature=False. This issue is fixed in version 2.15.0.
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Mon, 28 Sep 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | PyJWT is a Python implementation of JSON Web Token standards. From 2.0.0a1 until 2.15.0, PyJWT PyJWKClient.get_signing_key_from_jwt is affected because payload parser catches ValueError but not RecursionError. This occurs when an attacker-controlled recursively nested payload reaches json.loads. As a result, documented PyJWT exception handling does not contain the failure. Consequently, an unauthenticated request can raise an exception that may produce an HTTP 500 response. The advisory-defined affected implementation also includes jwt/api_jwt.py, verify_signature=False. This issue is fixed in version 2.15.0. | |
| Title | PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.get_signing_key_from_jwt / verify_signature=False) | |
| Weaknesses | CWE-248 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-28T20:11:55.278Z
Reserved: 2026-09-28T15:55:37.908Z
Link: CVE-2026-101918
No data.
Status : Received
Published: 2026-09-28T21:17:13.410
Modified: 2026-09-28T21:17:13.410
Link: CVE-2026-101918
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OpenCVE Enrichment
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Weaknesses