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Fencer Vulns
medium 5.4

CVE-2026-41479 json

Authlib OAuth 2.0 authorization endpoint open redirects to attacker-controlled redirect_uri on unsupported response_type

published 2026-06-08 5 mo ago modified 2026-07-18 3 mo ago also EUVD-2026-38360 , GHSA-w8p2-r796-3vmq , PYSEC-2026-2119

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.6.10 and 1.7.1, Authlib's OAuth 2.0 authorization endpoint can be turned into an unauthenticated open redirect when a request uses an unsupported response_type and supplies an attacker-controlled redirect_uri. The vulnerable behavior happens before client lookup and before any redirect URI validation. As a result, an attacker does not need a valid client registration, an authenticated user, or any prior state. A single request to the authorization endpoint is enough to obtain a 302 Location response to an arbitrary attacker-controlled URL. This vulnerability is fixed in 1.6.10 and 1.7.1.

Patch / fix

  • pypi authlib 1.6.10, 1.7.1
  • authlib authlib 1.6.10, 1.7.1
  • python-authlib Debian 14 1.7.2-1

debian advisories DEBIAN-CVE-2026-41479

  • python-Authlib SLE Module for Python 3 15 SP7 1.3.1-150600.3.30.1

suse advisories SUSE-SU-2026:4111-1

  • python-Authlib openSUSE Leap 16.0 1.5.2-bp160.4.1

opensuse advisories openSUSE-SU-2026:21795-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-41479 updated cvss 5.4

authlib: Authlib: Open Redirect vulnerability via crafted authorization requests

  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/lightspeed-chatbot-rhel9, ansible-automation-platform-27/lightspeed-chatbot-rhel9 Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    affected: workaround, no fix available “Upgrade Authlib to version 1.6.10 or later (for the 1.6.x series) or version 1.7.1 or later (for the 1.7.x series).”
  • Red Hat Lightspeed Core lightspeed-core/lightspeed-stack-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-agentic-sandbox-rhel9 Red Hat Enterprise Linux command line assistant rhel-cla/rhel-knowledge-bridge-rhel10 Red Hat Hardened Images jaeger Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9 Red Hat Satellite 6 satellite/foreman-mcp-server-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/authlib/authlib/security/advisories/GHSA-w8p2-r796-3vmq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi authlib
<1.6.10
>=1.7.0, <1.7.1
1.6.10
1.7.1

Affected products

  • authlib authlib

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.