UBUNTU-CVE-2026-27962

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Source
https://ubuntu.com/security/CVE-2026-27962
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27962.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-27962
Upstream
Published
2026-03-16T18:16:00Z
Modified
2026-04-27T18:56:13.397887Z
Severity
  • 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
  • Ubuntu - medium
Summary
[none]
Details

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any JWS deserialization function, the library extracts and uses the cryptographic key embedded in the attacker-controlled JWT jwk header field. An attacker can sign a token with their own private key, embed the matching public key in the header, and have the server accept the forged token as cryptographically valid — bypassing authentication and authorization entirely. 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_name": "python3-authlib",
            "binary_version": "0.15.5-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27962.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_name": "python3-authlib",
            "binary_version": "1.3.0-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27962.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_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-2026-27962.json"

Ubuntu:26.04 / python-authlib

Package

Name
python-authlib
Purl
pkg:deb/ubuntu/python-authlib@1.6.7-1?arch=source&distro=resolute

Affected ranges

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

Affected versions

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

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-authlib",
            "binary_version": "1.6.7-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27962.json"