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CVE-2026-114614— Authlib: is_secure_transport() loopback exemption can be bypassed with a userinfo component, allowing cleartext-HTTP URLs to non-loopback hosts

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 是一个用于构建 OAuth 和 OpenID Connect（OIDC）服务器的 Python 库。在版本 0.13 至 1.8.0 期间， 函数在检查回环（loopback）HTTP 例外时，使用了基于文本前缀的比较方式。这导致：如果某个 URL 的用户信息（userinfo）部分以回环主机名开头，即使该 URL 解析后的实际主机是外部非回环系统，该 URL 仍可能被接受。 若攻击者能够向以下场景提供恶意 URL： OIDC 的 RP 发起的注销（RP-Initiated Logout）动态客户端

CVSS 2.6 · Low
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I. Basic Information for CVE-2026-114614

Vulnerability Information
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Vulnerability Title
Authlib: is_secure_transport() loopback exemption can be bypassed with a userinfo component, allowing cleartext-HTTP URLs to non-loopback hosts
Source: CVE Program / CVE List V5
Vulnerability Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.13 until 1.8.0, authlib.common.security.is_secure_transport() uses a textual prefix comparison for loopback HTTP exemptions, so a URL whose userinfo begins with a loopback host can be accepted even when its parsed host is an external non-loopback system. An external party able to supply a URL to OIDC RP-Initiated Logout registration, authorization-server metadata validation, or another call site can bypass the TLS-required guard and cause cleartext redirection or acceptance of cleartext endpoints. The issue does not bypass redirect URI exact matching and does not by itself forge tokens or authenticate users. The vulnerable authlib.common.security.is_secure_transport() implementation in authlib/common/security.py misinterprets the userinfo component before OIDC RP-Initiated Logout dynamic client registration and other consumers enforce transport security. This issue is fixed in version 1.8.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
指向未可信站点的URL重定向(开放重定向)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
authlib authlib < 1.8.0 -

II. Public POCs for CVE-2026-114614

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III. Intelligence Information for CVE-2026-114614

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Patches & Fixes for CVE-2026-114614 (1)

Vendor Advisories for CVE-2026-114614 (1)

Vendor Pages for CVE-2026-114614 (1)

Same Patch Batch · authlib · 2026-10-22 · 7 CVEs total

CVE-2026-114615 7.4 HIGH Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keys
CVE-2026-114616 7.4 HIGH Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)
CVE-2026-114618 6.8 MEDIUM Authlib: Default JWT bearer grant accepts assertions for the wrong audience
CVE-2026-114620 5.4 MEDIUM Authlib: Unvalidated request_uri fetch in JWT-secured authorization request (JAR) leading
CVE-2026-114619 4.6 MEDIUM Authlib: OpenID implicit grant checks raw scope instead of allowed scope before issuing ID
CVE-2026-114617 4.2 MEDIUM Authlib: ID token can disable its own nonce validation via the nonce_supported claim

IV. Related Vulnerabilities

Same product: authlib
Same vendor: authlib
Same weakness: CWE-601

V. Comments for CVE-2026-114614

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