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.osv.dev/v1/vulns/UBUNTU-CVE-2026-28498
Upstream
Published
2026-03-16T18:16:00Z
Modified
2026-03-20T08:06:32.769002Z
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
  • 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 (verifyhash) responsible for validating the athash (Access Token Hash) and chash (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@0.15.5-1ubuntu0.1~esm1?arch=source&distro=esm-apps/jammy

Affected ranges

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

Affected versions

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "0.15.5-1ubuntu0.1~esm1",
            "binary_name": "python3-authlib"
        }
    ]
}

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@1.3.0-1ubuntu0.1~esm1?arch=source&distro=esm-apps/noble

Affected ranges

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

Affected versions

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.3.0-1ubuntu0.1~esm1",
            "binary_name": "python3-authlib"
        }
    ]
}

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@1.6.0-1?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown 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_version": "1.6.0-1",
            "binary_name": "python3-authlib"
        }
    ]
}

Database specific

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