USN-8823-1: PyJWT vulnerabilities

Publication date

25 September 2026

Overview

Several security issues were fixed in PyJWT.


Packages

  • pyjwt - Python 3 implementation of JSON Web Token

Details

It was discovered that PyJWT incorrectly handled certain URIs when using
PyJWKClient. A remote attacker could possibly use this issue to perform
server-side request forgery (SSRF) or expose sensitive local files.
This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu
26.04 LTS. (CVE-2026-48522)

It was discovered that PyJWT incorrectly verified cryptographic signatures
when decoding tokens with PyJWK keys. A remote attacker could possibly
use this issue to bypass signature verification and forge valid JSON Web
Tokens. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-48523)

It was discovered that PyJWT incorrectly handled unknown key identifiers
in PyJWKClient. A remote attacker could possibly use this issue to cause
PyJWT to make excessive network requests, resulting in a denial of service.
This issue only affected Ubuntu 24.04...

It was discovered that PyJWT incorrectly handled certain URIs when using
PyJWKClient. A remote attacker could possibly use this issue to perform
server-side request forgery (SSRF) or expose sensitive local files.
This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu
26.04 LTS. (CVE-2026-48522)

It was discovered that PyJWT incorrectly verified cryptographic signatures
when decoding tokens with PyJWK keys. A remote attacker could possibly
use this issue to bypass signature verification and forge valid JSON Web
Tokens. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-48523)

It was discovered that PyJWT incorrectly handled unknown key identifiers
in PyJWKClient. A remote attacker could possibly use this issue to cause
PyJWT to make excessive network requests, resulting in a denial of service.
This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS.
(CVE-2026-48524)

It was discovered that PyJWT incorrectly handled payload decoding during
detached JWS token verification. A remote attacker could possibly use
this issue to cause PyJWT to consume excessive resources, resulting in
a denial of service. This issue only affected Ubuntu 24.04 LTS and
Ubuntu 26.04 LTS. (CVE-2026-48525)

It was discovered that PyJWT incorrectly validated JSON Web Keys when
decoding tokens with both HMAC and asymmetric algorithms enabled. A remote
attacker could possibly use this issue to forge valid tokens, resulting
in an authentication bypass. (CVE-2026-48526)


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
26.04 LTS resolute python3-jwt –  2.10.1-4ubuntu1.1
24.04 LTS noble python3-jwt –  2.7.0-1ubuntu0.2
22.04 LTS jammy python3-jwt –  2.3.0-1ubuntu0.4
20.04 LTS focal python3-jwt –  1.7.1-2ubuntu2.1+esm2  
18.04 LTS bionic python-jwt –  1.5.3+ds1-1ubuntu0.1+esm2  
python3-jwt –  1.5.3+ds1-1ubuntu0.1+esm2  
16.04 LTS xenial python-jwt –  1.3.0-1ubuntu0.1+esm2  
python3-jwt –  1.3.0-1ubuntu0.1+esm2  

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