CVE-2025-65015

Nov. 19, 2025, 7:14 p.m.

9.2
Critical

Description

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions from 1.3.3 to before 1.3.5 and from 1.4.0 to before 1.4.2, the ExceededSizeError exception messages are embedded with non-decoded JWT token parts and may cause Python logging to record an arbitrarily large, forged JWT payload. In situations where a misconfigured — or entirely absent — production-grade web server sits in front of a Python web application, an attacker may be able to send arbitrarily large bearer tokens in the HTTP request headers. When this occurs, Python logging or diagnostic tools (e.g., Sentry) may end up processing extremely large log messages containing the full JWT header during the joserfc.jwt.decode() operation. The same behavior also appears when validating claims and signature payload sizes, as the library raises joserfc.errors.ExceededSizeError() with the full payload embedded in the exception message. Since the payload is already fully loaded into memory at this stage, the library cannot prevent or reject it. This issue has been patched in versions 1.3.5 and 1.4.2.

Product(s) Impacted

Vendor Product Versions
Joserfc
  • Joserfc
  • 1.3.3-1.3.4, 1.4.0-1.4.1

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-770
Allocation of Resources Without Limits or Throttling
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a joserfc joserfc 1.3.3-1.3.4 / / / / / / /
a joserfc joserfc 1.4.0-1.4.1 / / / / / / /

References

https://github.com/authlib/joserfc/commit/63932f169d924caffafa761af2122b82059017f7
https://github.com/authlib/joserfc/commit/673c8743fd0605b0e1de6452be6cba75f44e466b
https://github.com/authlib/joserfc/releases/tag/1.3.5
https://github.com/authlib/joserfc/releases/tag/1.4.2
https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4
https://github.com/authlib/joserfc/security/advisories/GHSA-frfh-8v73-gjg4

Tags

security-advisories@github.com
CWE-770
2025-11-18
CVE-2025-65015

CVSS Score

9.2 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Attack Requirements: NONE
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: HIGH
  • Exploit Maturity: NOT_DEFINED

    • CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

    View Vector String

Timeline

Published: Nov. 18, 2025, 11:15 p.m.
Last Modified: Nov. 19, 2025, 7:14 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

security-advisories@github.com

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.