# CVE-2026-48525: python3-jwt: PyJWT is a JSON Web Token implementation in Python

CVE-2026-48525 is fixed in 4 products on 1 platform, first by python3-jwt 2.7.0-1ubuntu0.2, released May 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-48525
- Priority: Routine
- CVSS: 5.3 (Medium)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 28, 2026

## Description

PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | pyjwt Debian 14 | 2.13.0-1 | [DEBIAN-CVE-2026-48525](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48525.md) | May 28, 2026 |
| Linux | python-PyJWT opensuse-leap 16.0 | 2.12.1-160000.2.1 | [OPENSUSE-SU-2026:21095-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21095-1.md) | Jun 19, 2026 |
| Linux | python-PyJWT sles 15.6 | 2.4.0-150200.3.14.1 | [SUSE-SU-2026:2627-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2627-1.md) | Jun 25, 2026 |
| Linux | python-PyJWT sles 15.7 | 2.4.0-150200.3.14.1 | [SUSE-SU-2026:2627-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2627-1.md) | Jun 25, 2026 |
| Linux | python-PyJWT sles 16.0 | 2.12.1-160000.2.1 | [SUSE-SU-2026:22170-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22170-1.md) | Jun 19, 2026 |
| Linux | python3-jwt Ubuntu 24.04.5 LTS (noble) | 2.7.0-1ubuntu0.2 | [python3-jwt 2.7.0-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-jwt-2.7.0-1ubuntu0.2.md) | May 28, 2026 |
| Linux | python3-jwt Ubuntu 26.04.1 LTS (resolute) | 2.10.1-4ubuntu1.1 | [python3-jwt 2.10.1-4ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-python3-jwt-2.10.1-4ubuntu1.1.md) | May 28, 2026 |
| Linux | python3-jwt amzn 2023 | 2.4.0-1.amzn2023.0.5 | [ALAS2023-2026-2051](https://patchblox.com/security/data/fix/linux/alas2023-2026-2051.md) | Aug 17, 2026 |
| Linux | python3-jwt+crypto amzn 2023 | 2.4.0-1.amzn2023.0.5 | [ALAS2023-2026-2051](https://patchblox.com/security/data/fix/linux/alas2023-2026-2051.md) | Aug 17, 2026 |

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Data as of 2026-11-08T13:06:02Z 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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