CVE-2025-62706— Authlib : JWE zip=DEF decompression bomb enables DoS
Quick assessment
Affected
authlib authlib
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Authlib是Authlib开源的一个构建 OAuth 和 OpenID Connect 服务器的终极 Python 库。 Authlib 1.6.5之前版本存在安全漏洞，该漏洞源于JWE zip=DEF路径执行无限制DEFLATE解压缩，可能导致内存和CPU耗尽，造成拒绝服务攻击。
Possible ATT&CK Techniques 1 AI
T1496 · Resource Hijacking
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I. Basic Information for CVE-2025-62706
Vulnerability Information
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Vulnerability Title
Authlib : JWE zip=DEF decompression bomb enables DoS
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
Authlib 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Authlib是Authlib开源的一个构建 OAuth 和 OpenID Connect 服务器的终极 Python 库。 Authlib 1.6.5之前版本存在安全漏洞，该漏洞源于JWE zip=DEF路径执行无限制DEFLATE解压缩，可能导致内存和CPU耗尽，造成拒绝服务攻击。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2025-62706
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Vendor Advisories for CVE-2025-62706 (1)
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V. Comments for CVE-2025-62706
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