CVE-2026-28802 (GCVE-0-2026-28802)

Vulnerability from cvelistv5 – Published: 2026-03-06 06:44 – Updated: 2026-03-06 16:05
VLAI?
Title
Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
Summary
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.
Severity ?
7.7 (High)
CVSS: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
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
Vendor Product Version
authlib authlib Affected: >= 1.6.5, < 1.6.7
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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