Allocation of Resources Without Limits or Throttling Affecting authlib package, versions [,1.6.5)
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Start learning- Snyk IDSNYK-PYTHON-AUTHLIB-13535082
- published12 Oct 2025
- disclosed10 Oct 2025
- creditMuhammad Noman Ilyas
Introduced: 10 Oct 2025
NewCVE-2025-62706 (opens in a new tab)How to fix?
Upgrade authlib to version 1.6.5 or higher.
Overview
authlib is a library in building OAuth and OpenID Connect servers.
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the DeflateZipAlgorithm.decompress function. An attacker can exhaust memory and CPU resources by submitting specially crafted compressed tokens that, when decrypted, expand to a much larger size than the original input.
Workaround
- Reject or strip
zip=DEFfor inbound JWEs at the application boundary until a fix is available. - Fork and add a bounded decompression guard (e.g.,
zlib.decompress(..., max_length)viadecompressobj().decompress(data, MAX_SIZE)), returning an error when output exceeds a safe limit. - Enforce strict maximum token sizes and fail fast on oversized inputs; combine with rate limiting.