by Kastro CVE-2026-28802
authlib authlib — Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
authlib>= 1.6.5, < 1.6.7–CNA
Red Hat Ansible Automation Platform 2.6see advisory1774417022redhat-SADP
Red Hat Quay 3.10see advisory1773971077redhat-SADP
Red Hat Quay 3.12see advisory1773771962redhat-SADP
Red Hat Quay 3.15see advisory1775169219redhat-SADP
Red Hat Quay 3.16see advisory1779204086redhat-SADP
Red Hat Quay 3.9see advisory1773936323redhat-SADP
Red Hat Satellite 6see advisory–redhat-SADP
Scores by source
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
redhat-SADP (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
GitHub_M (CNA)7.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial