Skip to content
Fencer Vulns
medium 6.8

CVE-2026-114618 json

Authlib: Default JWT bearer grant accepts assertions for the wrong audience

published 2026-10-22 17 d ago modified 2026-10-30 9 d ago also GHSA-fch4-3c6x-j4gc , PYSEC-2026-4358 , EUVD-2026-108520

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, the default RFC 7523 JWTBearerGrant.get_audiences() returns an empty list, causing JWTBearerGrant.verify_claims() to require only that an aud claim exists without matching the current authorization server. An attacker holding a legitimate assertion for another service can present it to a server that shares the signing key and uses the default grant, obtaining an access token across a trust boundary. Implementations that override get_audiences() with the server's valid audience identifiers are not affected. This issue is fixed in version 1.9.0.

Patch / fix

  • pypi authlib 1.9.0
  • authlib authlib 1.9.0
  • python-authlib Debian 14 1.9.1-1

debian advisories DEBIAN-CVE-2026-114618

  • python-Authlib openSUSE Tumbleweed 1.9.1-1.1

opensuse advisories openSUSE-SU-2026:12390-1

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-2026-114618 updated cvss 6.8

authlib: Authlib: Unauthorized access via improper JWT audience validation

  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Lightspeed Core lightspeed-core/lightspeed-stack-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-agentic-sandbox-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/lightspeed-chatbot-rhel9, ansible-automation-platform-27/lightspeed-chatbot-rhel9 Red Hat Enterprise Linux command line assistant rhel-cla/rhel-knowledge-bridge-rhel10 Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Satellite 6 satellite/foreman-mcp-server-rhel9
    affected: no fix available “Fix deferred”

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
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
10 d ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/authlib/authlib/security/advisories/GHSA-fch4-3c6x-j4gc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi authlib
<1.9.0
1.9.0

Affected products

  • authlib authlib

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-1188 Initialization of a Resource with an Insecure Default

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.