UBUNTU-CVE-2026-28498

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Source
https://ubuntu.com/security/CVE-2026-28498
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28498.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-28498
Upstream
Downstream
Related
Published
2026-03-16T18:16:00Z
Modified
2026-07-17T01:21:45Z
Severity
  • 8.2 (High) CVSS_V4 - 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 CVSS Calculator
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:Pro:22.04:LTS / python-authlib

Package

Name
python-authlib
Purl
pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fjammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
0.15.5-1ubuntu0.1~esm2

Affected versions

0.*
0.15.4-1
0.15.5-1
0.15.5-1ubuntu0.1~esm1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python3-authlib",
            "binary_version": "0.15.5-1ubuntu0.1~esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28498.json"

Ubuntu:Pro:24.04:LTS / python-authlib

Package

Name
python-authlib
Purl
pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.3.0-1ubuntu0.1~esm2

Affected versions

1.*
1.2.1-1
1.3.0-1
1.3.0-1ubuntu0.1~esm1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python3-authlib",
            "binary_version": "1.3.0-1ubuntu0.1~esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28498.json"

Ubuntu:25.10 / python-authlib

Package

Name
python-authlib
Purl
pkg:deb/ubuntu/python-authlib?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.5.1-1
1.5.2-1
1.6.0-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-authlib",
            "binary_version": "1.6.0-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28498.json"

Ubuntu:Pro:26.04:LTS / python-authlib

Package

Name
python-authlib
Purl
pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fresolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1.6.7-1ubuntu0.1~esm1

Affected versions

1.*
1.6.0-1
1.6.5-1
1.6.6-1
1.6.7-1

Ecosystem specific 

{
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python3-authlib",
            "binary_version": "1.6.7-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28498.json"