CVE-2025-62706
Fixed in a distro release EPSS <1%CVSS 6.5
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.
Products: authlib
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| PyPI | authlib | 1.6.5 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | mlflow | 3.4.0-r2 |
| Chainguard | mlflow-iamguarded-compat | 3.4.0-r2 |
| Debian 11 | python-authlib | 0.15.4-1+deb11u1 |
| Debian 12 | python-authlib | 1.2.0-1+deb12u1 |
| Debian 13 | python-authlib | 1.6.0-1+deb13u1 |
| Debian 14 | python-authlib | 1.6.5-1 |
| SUSE Linux Enterprise Module for Python 3 15 SP6 | python-Authlib | 1.3.1-150600.3.9.1 |
| SUSE Linux Enterprise Module for Python 3 15 SP7 | python-Authlib | 1.3.1-150600.3.9.1 |
| Ubuntu 25.10 | python-authlib | no fix |
| Ubuntu Pro 22.04 LTS | python-authlib | 0.15.5-1ubuntu0.1~esm1 |
| Ubuntu Pro 24.04 LTS | python-authlib | 1.3.0-1ubuntu0.1~esm1 |
| Ubuntu Pro 26.04 LTS | python-authlib | no fix |
| Wolfi | mlflow | 3.4.0-r2 |
| Wolfi | mlflow-iamguarded-compat | 3.4.0-r2 |
| openSUSE Leap 15.6 | python-Authlib | 1.3.1-150600.3.9.1 |