Upstream information

CVE-2026-28498 at MITRE

Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a library-level vulnerability was identified in the Authlib Python library concerning the validation of OpenID Connect (OIDC) ID Tokens. Specifically, the internal hash verification logic (_verify_hash) responsible for validating the at_hash (Access Token Hash) and c_hash (Authorization Code Hash) claims exhibits a fail-open behavior when encountering an unsupported or unknown cryptographic algorithm. This flaw allows an attacker to bypass mandatory integrity protections by supplying a forged ID Token with a deliberately unrecognized alg header parameter. The library intercepts the unsupported state and silently returns True (validation passed), inherently violating fundamental cryptographic design principles and direct OIDC specifications. This issue has been patched in version 1.6.9.

SUSE information

Overall state of this security issue: Pending

This issue is currently rated as having critical severity.

CVSS v3 Scores
CVSS detail SUSE
Base Score 9.1
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact None
CVSSv3 Version 3.1
CVSS v4 Scores
CVSS detail CNA (GitHub) SUSE
Base Score 8.2 9.1
Vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/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 CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Attack Vector Network Network
Attack Complexity High High
Attack Requirements Present None
Privileges Required None None
User Interaction None None
Vulnerable System Confidentiality Impact None High
Vulnerable System Integrity Impact High High
Vulnerable System Availability Impact None None
Subsequent System Confidentiality Impact None None
Subsequent System Integrity Impact None None
Subsequent System Availability Impact None None
CVSSv4 Version 4.0 4.0
SUSE Bugzilla entry: 1259737 [NEW]

No SUSE Security Announcements cross referenced.

List of packages in QA

Product(s) Package(s)
SUSE Linux Enterprise Module for Python 3 15 SP7
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Server 15 SP7
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Desktop 15 SP7
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Server for SAP Applications 15 SP7
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise High Performance Computing 15 SP7
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Server 15 SP6-LTSS
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Server 15 SP6-LTSS
  • python311-Authlib >= 1.3.1-150600.3.17.1
SUSE Linux Enterprise Server for SAP Applications 15 SP6
  • python311-Authlib >= 1.3.1-150600.3.17.1

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP7 python-Authlib In progress
SUSE Linux Enterprise High Performance Computing 15 SP7 python-Authlib In progress
SUSE Linux Enterprise Module for Python 3 15 SP7 python-Authlib In progress
SUSE Linux Enterprise Server 15 SP7 python-Authlib In progress
SUSE Linux Enterprise Server for SAP Applications 15 SP7 python-Authlib In progress
openSUSE Leap 15.6 python-Authlib Affected
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise Server 15 SP6-LTSS python-Authlib In progress
SUSE Linux Enterprise Server for SAP Applications 15 SP6 python-Authlib In progress
Products past their end of life and not receiving proactive updates anymore.
SUSE Linux Enterprise Desktop 15 SP6 python-Authlib Affected
SUSE Linux Enterprise High Performance Computing 15 SP6 python-Authlib Affected
SUSE Linux Enterprise Module for Python 3 15 SP6 python-Authlib Affected
SUSE Linux Enterprise Server 15 SP6 python-Authlib Affected

SUSE Timeline for this CVE

CVE page created: Mon Mar 16 20:00:42 2026
CVE page last modified: Tue Mar 17 20:47:28 2026