---
title: "CVE-2026-102272: PyJWT - Authentication Bypass"
description: "PyJWT 2.13.0 to < 2.14.0 contains an authentication bypass caused by improper normalization of Unicode byte-order marks in raw-JWK detection in HMACAlgorithm.prepare_key, letting attackers forge tokens using public keys, exploit requires use of mixed-algorithm verification with public JWK prefixed by UTF-8 BOM."
url: https://panop.io/threat-heartbeat/CVE-2026-102272/
---

# CVE-2026-102272 PyJWT - Authentication Bypass

PyJWT 2.13.0 to < 2.14.0 contains an authentication bypass caused by improper normalization of Unicode byte-order marks in raw-JWK detection in HMACAlgorithm.prepare\_key, letting attackers forge tokens using public keys, exploit requires use of mixed-algorithm verification with public JWK prefixed by UTF-8 BOM.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

Proof of concept available

EPSS

0.18% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-102272)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Published

28 September 2026

Updated

15 October 2026

Weakness

[CWE-347](https://cwe.mitre.org/data/definitions/347.html)

## Vendor fix

Upgrade to version 2.14.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-102272](https://nvd.nist.gov/vuln/detail/CVE-2026-102272)
- [https://github.com/jpadilla/pyjwt/commit/180783930de91876bc0d601f826a1f2956057291](https://github.com/jpadilla/pyjwt/commit/180783930de91876bc0d601f826a1f2956057291)
- [https://github.com/jpadilla/pyjwt/releases/tag/2.14.0](https://github.com/jpadilla/pyjwt/releases/tag/2.14.0)
- [https://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947](https://github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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