# CVE-2026-102273: PyJWT accepts public JWK containers as HMAC secrets

CVE-2026-102273 is fixed in 4 products on 1 platform, first by python3-jwt 2.10.1-4ubuntu1.2, released September 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-102273
- Priority: High
- CVSS: 7.4 (Important)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 28, 2026
- Weakness: Improper Verification of Cryptographic Signature
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102273

## Description

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | pyjwt Debian 14 | 2.14.0-1 | [DEBIAN-CVE-2026-102273](https://patchblox.com/security/data/fix/linux/debian-cve-2026-102273.md) | Oct 4, 2026 |
| Linux | python-jwt Ubuntu 18.04.6 LTS (bionic) | 1.5.3+ds1-1ubuntu0.1+esm3 | [python-jwt 1.5.3+ds1-1ubuntu0.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-jwt-1.5.3-ds1-1ubuntu0.1-esm3.md) | Oct 27, 2026 |
| Linux | python3-jwt Ubuntu 18.04.6 LTS (bionic) | 1.5.3+ds1-1ubuntu0.1+esm3 | [python3-jwt 1.5.3+ds1-1ubuntu0.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-jwt-1.5.3-ds1-1ubuntu0.1-esm3.md) | Oct 27, 2026 |
| Linux | python3-jwt Ubuntu 20.04 LTS (focal) | 1.7.1-2ubuntu2.1+esm3 | [python3-jwt 1.7.1-2ubuntu2.1+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-jwt-1.7.1-2ubuntu2.1-esm3.md) | Oct 27, 2026 |
| Linux | python3-jwt Ubuntu 22.04.1 LTS (jammy) | 2.3.0-1ubuntu0.5 | [python3-jwt 2.3.0-1ubuntu0.5](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-jwt-2.3.0-1ubuntu0.5.md) | Oct 27, 2026 |
| Linux | python3-jwt Ubuntu 24.04.5 LTS (noble) | 2.7.0-1ubuntu0.3 | [python3-jwt 2.7.0-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-jwt-2.7.0-1ubuntu0.3.md) | Oct 27, 2026 |
| Linux | python3-jwt Ubuntu 26.04.1 LTS (resolute) | 2.10.1-4ubuntu1.2 | [python3-jwt 2.10.1-4ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-jwt-2.10.1-4ubuntu1.2.md) | Sep 28, 2026 |
| Linux | python3-jwt amzn 2023 | 2.4.0-1.amzn2023.0.6 | [ALAS2023-2026-3298](https://patchblox.com/security/data/fix/linux/alas2023-2026-3298.md) | Nov 7, 2026 |
| Linux | python3-jwt+crypto amzn 2023 | 2.4.0-1.amzn2023.0.6 | [ALAS2023-2026-3298](https://patchblox.com/security/data/fix/linux/alas2023-2026-3298.md) | Nov 7, 2026 |

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Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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