CVE-2026-28802

CRITICALNVD 9.89.8
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(low)
EPSS
34.8%
KEV
Not listed

Published

March 6, 2026

Last Modified

July 20, 2026

Advisory Details (10)

Auto-updated Jul 20, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github, redhat.
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-28802
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6568
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:6309
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:5665
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:5168
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:4942
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:19375
github Patch Available🟡 PoC Available

Setting `alg: none` and a blank signature appears to bypass signature verification · Advisory · authlib/authlib · GitHub

https://github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8gg
github_commit Patch Available

commit b87c32ed07b8 (authlib/authlib)

Patch available: authlib/authlib v1.6.7 (contains commit b87c32ed07b8)

https://github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7
github_commit Patch Available

commit a61c2acb8074 (authlib/authlib)

Patch available: authlib/authlib v1.6.0 (contains commit a61c2acb8074)

https://github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75

Vendor Advisories for CVE-2026-28802(7)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatquay/quay-rhel9:17792040862026-05-19redhat
redhatquay/quay-rhel8:17751692192026-04-03redhat
redhatansible-automation-platform-26/lightspeed-chatbot-rhel9:17744170222026-04-01redhat
redhatquay/quay-rhel8:17739710772026-03-24redhat
redhatquay/quay-rhel8:17739363232026-03-19redhat
redhatquay/quay-rhel8:17737719622026-03-18redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
authlib1.6.5, 1.6.61.6.7—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-21 15:24 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 02:29 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-18 06:59 UTCOSV refresh
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-16 17:03 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 02:22 UTCNVD updateCVSS v3 → 9.8
  18. 2026-07-15 02:00 UTCEPSS rescore
  19. 2026-07-15 02:00 UTCEPSS rescore
  20. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 9.1
  21. 2026-07-13 22:30 UTCEPSS rescore
  22. 2026-07-13 06:13 UTCEPSS rescore
  23. 2026-07-13 06:13 UTCEPSS rescore
  24. 2026-07-12 05:46 UTCEPSS rescore
  25. 2026-07-11 08:27 UTCEPSS rescore
Show 15 more
  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-08 15:15 UTCEPSS rescore
  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-01 15:06 UTCEPSS rescore
  11. 2026-06-30 23:22 UTCEPSS rescore
  12. 2026-06-30 23:22 UTCEPSS rescore
  13. 2026-06-30 04:34 UTCEG score recompute
  14. 2026-06-30 04:34 UTCVendor advisory
  15. 2026-06-30 04:31 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-28802?
CVE-2026-28802 is a critical vulnerability published on March 6, 2026. 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 was CVE-2026-28802 disclosed?
CVE-2026-28802 was first published in the National Vulnerability Database on March 6, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28802 actively exploited?
CVE-2026-28802 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-28802?
CVE-2026-28802 has a CVSS v3 base score of 9.8 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-28802?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28802, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-28802

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