Home / mailings

PDF

[USN-8916-1] PyJWT vulnerabilities

Posted on 14 October 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-8916-1
October 13, 2026

pyjwt vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 26.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in PyJWT.

Software Description:
- pyjwt: Python 3 implementation of JSON Web Token

Details:

YuSung Han discovered that PyJWT did not properly validate certain JWK keys
when performing HMAC verification. An attacker could possibly use this
issue to forge authentication tokens. This issue only affected Ubuntu
26.04 LTS. (CVE-2026-102266)

Rohan Das discovered that PyJWT incorrectly handled redirects when fetching
key sets. A remote attacker could possibly use this issue to cause PyJWT
to disclose sensitive information. This issue only affected Ubuntu 22.04
LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS. (CVE-2026-102267)

It was discovered that PyJWT incorrectly recognized certain PEM
representations. An attacker who knew the public key could possibly use
this issue to forge authentication tokens. This issue only affected Ubuntu
18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu
26.04 LTS. (CVE-2026-102268)

Nuno Lopes discovered that PyJWT incorrectly handled DER public keys when
performing HMAC verification. An attacker who knew the public key could
possibly use this issue to forge authentication tokens. (CVE-2026-102271)

It was discovered that PyJWT did not properly handle certain JWK keys
prefixed with a byte-order mark. An attacker who knew the public key could
possibly use this issue to forge authentication tokens. (CVE-2026-102272)

Charles Vosburgh discovered that PyJWT incorrectly handled certain JWK
containers when performing HMAC verification. An attacker who knew the
public key could possibly use this issue to forge authentication tokens.
(CVE-2026-102273)

Update instructions:

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

Ubuntu 26.04 LTS
python3-jwt 2.10.1-4ubuntu1.2

Ubuntu 24.04 LTS
python3-jwt 2.7.0-1ubuntu0.3

Ubuntu 22.04 LTS
python3-jwt 2.3.0-1ubuntu0.5

Ubuntu 20.04 LTS
python3-jwt 1.7.1-2ubuntu2.1+esm3
Available with Ubuntu Pro

Ubuntu 18.04 LTS
python-jwt 1.5.3+ds1-1ubuntu0.1+esm3
Available with Ubuntu Pro
python3-jwt 1.5.3+ds1-1ubuntu0.1+esm3
Available with Ubuntu Pro

Ubuntu 16.04 LTS
python-jwt 1.3.0-1ubuntu0.1+esm3
Available with Ubuntu Pro
python3-jwt 1.3.0-1ubuntu0.1+esm3
Available with Ubuntu Pro

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

References:
https://ubuntu.com/security/notices/USN-8916-1
CVE-2026-102266, CVE-2026-102267, CVE-2026-102268, CVE-2026-102271,
CVE-2026-102272, CVE-2026-102273

Package Information:
https://launchpad.net/ubuntu/+source/pyjwt/2.10.1-4ubuntu1.2
https://launchpad.net/ubuntu/+source/pyjwt/2.7.0-1ubuntu0.3
https://launchpad.net/ubuntu/+source/pyjwt/2.3.0-1ubuntu0.5

--===============5303455269788120418==Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature

 

TOP