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[USN-8823-1] PyJWT vulnerabilities

Posted on 28 September 2026
Ubuntu Security

==========================================================================Ubuntu Security Notice USN-8823-1
September 25, 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:

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:

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

Ubuntu 26.04 LTS
python3-jwt 2.10.1-4ubuntu1.1

Ubuntu 24.04 LTS
python3-jwt 2.7.0-1ubuntu0.2

Ubuntu 22.04 LTS
python3-jwt 2.3.0-1ubuntu0.4

Ubuntu 20.04 LTS
python3-jwt 1.7.1-2ubuntu2.1+esm2
Available with Ubuntu Pro

Ubuntu 18.04 LTS
python-jwt 1.5.3+ds1-1ubuntu0.1+esm2
Available with Ubuntu Pro
python3-jwt 1.5.3+ds1-1ubuntu0.1+esm2
Available with Ubuntu Pro

Ubuntu 16.04 LTS
python-jwt 1.3.0-1ubuntu0.1+esm2
Available with Ubuntu Pro
python3-jwt 1.3.0-1ubuntu0.1+esm2
Available with Ubuntu Pro

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

References:
https://ubuntu.com/security/notices/USN-8823-1
CVE-2026-48522, CVE-2026-48523, CVE-2026-48524, CVE-2026-48525,
CVE-2026-48526

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

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