CVE-2026-28802
Critical · CVSS 9.8Authlib — JWT algorithm confusion / "alg:none" signature bypass (CWE-347 Improper Verification of Cryptographic Signature)
- CVSS
- 9.8
- nvd
- EPSS
- 0.43%
- 35th pct
- KEV
- No
- Class
- oss containerizable
- CWE-347, CWE-347
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.
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Ranked PoCs (1) — best first
Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.
- ★ 0
Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.
Affected packages
| PyPI | authlib | 1.6.5 → 1.6.7 |
References
- https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75
- https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7
- https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg
- 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
Status: enriched · ingested 2026-06-30T06:00:22.000Z · profiled 2026-07-01T06:30:14.000Z