# CVE-2025-62706: python-authlib: Authlib is a Python library which builds OAuth and OpenID Connect servers

CVE-2025-62706 is fixed in 3 products on 1 platform, first by python3-authlib 0.15.5-1ubuntu0.1~esm1, released October 22, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-62706
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0046
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 22, 2025

## Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.5, Authlib’s JWE zip=DEF path performs unbounded DEFLATE decompression. A very small ciphertext can expand into tens or hundreds of megabytes on decrypt, allowing an attacker who can supply decryptable tokens to exhaust memory and CPU and cause denial of service. This issue has been patched in version 1.6.5. Workarounds for this issue involve rejecting or stripping zip=DEF for inbound JWEs at the application boundary, forking and add a bounded decompression guard via decompressobj().decompress(data, MAX_SIZE)) and returning an error when output exceeds a safe limit, or enforcing strict maximum token sizes and fail fast on oversized inputs; combine with rate limiting.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-Authlib opensuse-leap 15.6 | 1.3.1-150600.3.9.1 | [SUSE-SU-2025:3842-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3842-1.md) | Oct 28, 2025 |
| Linux | python-Authlib sles 15.6 | 1.3.1-150600.3.9.1 | [SUSE-SU-2025:3842-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3842-1.md) | Oct 28, 2025 |
| Linux | python-Authlib sles 15.7 | 1.3.1-150600.3.9.1 | [SUSE-SU-2025:3842-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-3842-1.md) | Oct 28, 2025 |
| Linux | python-authlib Debian 12.15 (bookworm) | 1.2.0-1+deb12u1 | [DEBIAN-CVE-2025-62706](https://patchblox.com/security/data/fix/linux/debian-cve-2025-62706.md) | Oct 22, 2025 |
| Linux | python-authlib Debian 13.5 (trixie) | 1.6.0-1+deb13u1 | [DEBIAN-CVE-2025-62706](https://patchblox.com/security/data/fix/linux/debian-cve-2025-62706.md) | Oct 22, 2025 |
| Linux | python-authlib Debian 14 | 1.6.5-1 | [DEBIAN-CVE-2025-62706](https://patchblox.com/security/data/fix/linux/debian-cve-2025-62706.md) | Oct 22, 2025 |
| Linux | python3-authlib Ubuntu 22.04.1 LTS (jammy) | 0.15.5-1ubuntu0.1~esm1 | [python3-authlib 0.15.5-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-python3-authlib-0.15.5-1ubuntu0.1-esm1.md) | Oct 22, 2025 |
| Linux | python3-authlib Ubuntu 24.04.5 LTS (noble) | 1.3.0-1ubuntu0.1~esm1 | [python3-authlib 1.3.0-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-python3-authlib-1.3.0-1ubuntu0.1-esm1.md) | Jan 8, 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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