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CVE-2025-62706

CVE-2025-62706 · Authlib : JWE zip=DEF decompression bomb enables DoS

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.5 · Medium · EPSS 0.5% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • authlib

    Versions
    • < 1.6.5: Affected

    No fix published

  • python-authlib Debian:12

    Versions
    • 1.2.0-1
    Affected ranges
    • ECOSYSTEM: < 1.2.0-1+deb12u1

    Update to 1.2.0-1+deb12u1

  • python-authlib Debian:13

    Versions
    • 1.6.0-1
    Affected ranges
    • ECOSYSTEM: < 1.6.0-1+deb13u1

    Update to 1.6.0-1+deb13u1

  • python-authlib Debian:14

    Versions
    • 1.6.0-1
    • 1.6.1-1
    • 1.6.3-1
    • 1.6.4-1
    Affected ranges
    • ECOSYSTEM: < 1.6.5-1

    Update to 1.6.5-1

  • authlib PyPI

    Versions
    • 0.1
    • 0.10
    • 0.11
    • 0.12
    • 0.12.1
    • 0.13
    • 0.14
    • 0.14.1
    • 0.14.2
    • 0.14.3
    • 0.15
    • 0.15.1
    • 0.15.2
    • 0.15.3
    • 0.15.4
    • 0.15.5
    • 0.15.6
    • 0.1rc0
    • 0.2
    • 0.2.1
    • 0.3
    • 0.4
    • 0.4.1
    • 0.5
    • 0.5.1
    • 0.6
    • 0.7
    • 0.8
    • 0.9
    • 1.0.0
    • 1.0.0a1
    • 1.0.0a2
    • 1.0.0b1
    • 1.0.0b2
    • 1.0.0rc1
    • 1.0.1
    • 1.1.0
    • 1.2.0
    • 1.2.1
    • 1.3.0
    • 1.3.1
    • 1.3.2
    • 1.4.0
    • 1.4.1
    • 1.5.0
    • 1.5.1
    • 1.5.2
    • 1.6.0
    • 1.6.1
    • 1.6.2
    • 1.6.3
    • 1.6.4
    Affected ranges
    • ECOSYSTEM: < 1.6.5

    Update to 1.6.5

  • python-authlib Ubuntu:Pro:22.04:LTS

    Versions
    • 0.15.4-1
    • 0.15.5-1
    Affected ranges
    • ECOSYSTEM: < 0.15.5-1ubuntu0.1~esm1

    Update to 0.15.5-1ubuntu0.1~esm1

  • python-authlib Ubuntu:Pro:24.04:LTS

    Versions
    • 1.2.1-1
    • 1.3.0-1
    Affected ranges
    • ECOSYSTEM: < 1.3.0-1ubuntu0.1~esm1

    Update to 1.3.0-1ubuntu0.1~esm1

  • python-authlib Ubuntu:25.10

    Versions
    • 1.5.1-1
    • 1.5.2-1
    • 1.6.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-authlib Ubuntu:Pro:26.04:LTS

    Versions
    • 1.6.0-1
    • 1.6.5-1
    • 1.6.6-1
    • 1.6.7-1
    • 1.6.7-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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