7.7High
CVE-2026-28802Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.
Weakness (CWE):
CWE-347
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| ansible automation platform | 2.6 | — | |
| authlib | authlib | >= 1.6.5, < 1.6.7 | |
| quay | 3.10 | — | |
| quay | 3.12 | — | |
| quay | 3.15 | — | |
| quay | 3.16 | — | |
| quay | 3.9 | — | |
| Red Hat | Red Hat Ansible Automation Platform 2.6 | all versions | |
| Red Hat | Red Hat Quay 3.10 | all versions | |
| Red Hat | Red Hat Quay 3.12 | all versions | |
| Red Hat | Red Hat Quay 3.15 | all versions | |
| Red Hat | Red Hat Quay 3.16 | all versions | |
| Red Hat | Red Hat Quay 3.9 | all versions | |
| Red Hat | Red Hat Satellite 6 | all versions |
References and patches
- https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg ExploitVendor Advisory
- https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75 Patch
- https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7 Patch
- https://access.redhat.com/errata/RHSA-2026:19375
- https://access.redhat.com/errata/RHSA-2026:4942
- https://access.redhat.com/errata/RHSA-2026:5168
- https://access.redhat.com/errata/RHSA-2026:5665
- https://access.redhat.com/errata/RHSA-2026:6309
- https://access.redhat.com/errata/RHSA-2026:6568
- https://access.redhat.com/security/cve/CVE-2026-28802
- https://bugzilla.redhat.com/show_bug.cgi?id=2445120
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28802.json
CPE matches (NVD) (1)
cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:*≥ 1.6.5 < 1.6.7