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CVE-2026-114614VulnerabilityPublished

Authlib: is_secure_transport() loopback exemption can be bypassed with a userinfo component, allowing cleartext-HTTP

Affects authlibSource GCVE Database

0
Authoritative record:CVE-2026-114614· Low 2.6

Not known to be exploited · CVSS 2.6 Low : upgrade to 1.8.0 when convenient.

Data as of 27 Oct 2026, 16:29 UTC

CVSS 3.1 base score
2.6Low
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 1.8.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade authlib to 1.8.0.

Affected software

ProductAffectedFixed in
PyPIauthlibAffected
  • <1.8.0
Fixed in
  • 1.8.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Authlib version 1.8.0, which corrects the is_secure_transport() function to properly validate loopback exemptions without being bypassable by userinfo components. Users should upgrade to Authlib 1.8.0 or later. Until upgraded, users should carefully validate URLs and avoid relying solely on is_secure_transport() for security-critical decisions involving redirect URIs or endpoint metadata.

Description

Authlib versions from 0.13 up to 1.7.2 contain a vulnerability in the is_secure_transport() function, which incorrectly treats certain HTTP URLs with userinfo components as secure loopback addresses. This allows an attacker to bypass the TLS enforcement by crafting URLs like http://localhost:80@evil.example/cb, where the actual host is external but the function returns true due to a prefix string match. This flaw affects OAuth 2.0 / OIDC endpoint and redirect URI validation, potentially allowing cleartext HTTP URLs to be accepted where TLS is required. The issue is fixed in Authlib 1.8.0.

References

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