Bug 2542671 (CVE-2026-102266) - CVE-2026-102266 pyjwt: pyjwt: Authentication bypass via empty HMAC key acceptance
Summary: CVE-2026-102266 pyjwt: pyjwt: Authentication bypass via empty HMAC key accept...
Keywords:
Status: NEW
Alias: CVE-2026-102266
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-28 20:32 UTC by OSIDB Bzimport
Modified: 2026-11-12 05:28 UTC (History)
120 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:87004 0 None None None 2026-10-21 13:53:11 UTC
Red Hat Product Errata RHSA-2026:94500 0 None None None 2026-11-03 12:40:30 UTC
Red Hat Product Errata RHSA-2026:94501 0 None None None 2026-11-03 11:52:32 UTC
Red Hat Product Errata RHSA-2026:94523 0 None None None 2026-11-03 13:34:31 UTC
Red Hat Product Errata RHSA-2026:94557 0 None None None 2026-11-03 14:28:18 UTC
Red Hat Product Errata RHSA-2026:94634 0 None None None 2026-11-03 18:54:41 UTC
Red Hat Product Errata RHSA-2026:95012 0 None None None 2026-11-04 06:40:47 UTC
Red Hat Product Errata RHSA-2026:98503 0 None None None 2026-11-11 12:04:30 UTC
Red Hat Product Errata RHSA-2026:98612 0 None None None 2026-11-11 11:35:13 UTC

Description OSIDB Bzimport 2026-09-28 20:32:47 UTC 
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.
Comment 1 Jon Orris 2026-10-21 13:53:06 UTC 
This issue has been addressed in the following products:

  Red Hat Ansible Automation Platform 2.6 for RHEL 9
  Red Hat Ansible Automation Platform 2.6 for RHEL 10

Via RHSA-2026:87004 https://access.redhat.com/errata/RHSA-2026:87004
Comment 4 Jon Orris 2026-11-03 11:52:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:94501 https://access.redhat.com/errata/RHSA-2026:94501
Comment 5 Jon Orris 2026-11-03 12:40:23 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:94500 https://access.redhat.com/errata/RHSA-2026:94500
Comment 6 Jon Orris 2026-11-03 13:34:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:94523 https://access.redhat.com/errata/RHSA-2026:94523
Comment 7 Jon Orris 2026-11-03 14:28:12 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:94557 https://access.redhat.com/errata/RHSA-2026:94557
Comment 8 Jon Orris 2026-11-03 18:54:35 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:94634 https://access.redhat.com/errata/RHSA-2026:94634
Comment 9 Jon Orris 2026-11-04 06:40:40 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:95012 https://access.redhat.com/errata/RHSA-2026:95012
Comment 10 errata-xmlrpc 2026-11-11 11:35:05 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:98612 https://access.redhat.com/errata/RHSA-2026:98612
Comment 11 errata-xmlrpc 2026-11-11 12:04:23 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:98503 https://access.redhat.com/errata/RHSA-2026:98503
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