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.
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Affected Vendors & Products
Advisories
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GHSA-g7f3-828f-7h7m | Authlib : JWE zip=DEF decompression bomb enables DoS |
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Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 22 Oct 2025 21:45:00 +0000
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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. | |
Title | Authlib : JWE zip=DEF decompression bomb enables DoS | |
Weaknesses | CWE-400 CWE-770 |
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cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2025-10-22T21:31:10.997Z
Reserved: 2025-10-20T19:41:22.738Z
Link: CVE-2025-62706

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Status : Received
Published: 2025-10-22T22:15:35.557
Modified: 2025-10-22T22:15:35.557
Link: CVE-2025-62706

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