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CVE-2026-28802
Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
High7.7EPSS 0.54%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High7.7 | 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 |
| redhat-SADPADP (enrichment) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| NVDNVD · Modified | 4.0 | High7.7 | 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.54% · top 55% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.7.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIauthlibGHSA-7wc2-qxgw-g8gg (opens in a new tab)
References (12)
- https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg (opens in a new tab)x_refsource_CONFIRM
- https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75 (opens in a new tab)x_refsource_MISC
- https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7 (opens in a new tab)x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-28802 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2445120 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28802.json (opens in a new tab)x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:6309 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:5665 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:4942 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:6568 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:19375 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:5168 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-7wc2-qxgw-g8gg (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2026-28802)Record last updated .