UBUNTU-CVE-2026-102266

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Source
https://ubuntu.com/security/CVE-2026-102266
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102266.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-102266
Upstream
Downstream
USN (2)
Published
2026-09-28T21:17:00Z
Modified
2026-10-20T10:45:33Z
Severity
  • 7.4 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A: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
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:26.10 / pyjwt

Package

Name
pyjwt
Purl
pkg:deb/ubuntu/pyjwt?arch=source&distro=stonking

Affected ranges

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

Affected versions

2.*
2.10.1-4ubuntu1
2.12.1-1
2.13.0-1
2.13.0-1ubuntu1
2.13.0-1ubuntu1.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-jwt",
            "binary_version":  "2.13.0-1ubuntu1.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102266.json"

Ubuntu:26.04:LTS / pyjwt

Package

Name
pyjwt
Purl
pkg:deb/ubuntu/pyjwt?arch=source&distro=resolute

Affected ranges

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

Affected versions

2.*
2.10.1-2
2.10.1-3
2.10.1-3build1
2.10.1-4
2.10.1-4ubuntu1
2.10.1-4ubuntu1.1
2.10.1-4ubuntu1.2
2.10.1-4ubuntu1.3

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "python3-jwt",
            "binary_version":  "2.10.1-4ubuntu1.3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102266.json"