USN-8934-1: PyJWT vulnerabilities

Publication date

19 October 2026

Overview

Several security issues were fixed in PyJWT.


Packages

  • pyjwt - Python 3 implementation of JSON Web Token

Details

Kingsley Olukanni discovered that PyJWT did not properly handle unknown key
identifiers when retrieving signing keys. An attacker could possibly use
this issue to amplify requests to the configured key endpoint, resulting in
a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu
24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10. (CVE-2026-101917)

Ekalabya Ghosh discovered that PyJWT did not properly handle certain
recursively nested JSON payloads. An attacker could possibly use this issue
to cause an application to fail, resulting in a denial of service.
(CVE-2026-101918)

Pedram Hayati discovered that PyJWT did not properly handle malformed RSA
keys in a JSON Web Key Set. An attacker could possibly use this issue to
cause authentication failures or a denial of service. This issue only
affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu...

Kingsley Olukanni discovered that PyJWT did not properly handle unknown key
identifiers when retrieving signing keys. An attacker could possibly use
this issue to amplify requests to the configured key endpoint, resulting in
a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu
24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10. (CVE-2026-101917)

Ekalabya Ghosh discovered that PyJWT did not properly handle certain
recursively nested JSON payloads. An attacker could possibly use this issue
to cause an application to fail, resulting in a denial of service.
(CVE-2026-101918)

Pedram Hayati discovered that PyJWT did not properly handle malformed RSA
keys in a JSON Web Key Set. An attacker could possibly use this issue to
cause authentication failures or a denial of service. This issue only
affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS and Ubuntu
26.10. (CVE-2026-102274)

It was discovered that PyJWT did not properly validate certain OKP private
key components. An attacker could possibly use this issue to confuse the
identity of public and private keys, and use a stolen sender-constrained
token without the legitimate private key. This issue only affected Ubuntu
22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10.
(CVE-2026-102275)


Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.10 stonking python3-jwt –  2.13.0-1ubuntu1.1
26.04 LTS resolute python3-jwt –  2.10.1-4ubuntu1.3
24.04 LTS noble python3-jwt –  2.7.0-1ubuntu0.4
22.04 LTS jammy python3-jwt –  2.3.0-1ubuntu0.6
20.04 LTS focal python3-jwt –  1.7.1-2ubuntu2.1+esm4  
18.04 LTS bionic python-jwt –  1.5.3+ds1-1ubuntu0.1+esm4  
python3-jwt –  1.5.3+ds1-1ubuntu0.1+esm4  
16.04 LTS xenial python-jwt –  1.3.0-1ubuntu0.1+esm4  
python3-jwt –  1.3.0-1ubuntu0.1+esm4  

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