Is CVE-2026-28802 in the CISA KEV catalog?

No. CVE-2026-28802 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-28802?

CVE-2026-28802 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2026-28802?

CVE-2026-28802 has an EPSS score of 0.34% (25th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-28802

CRITICAL

9.8

CVSS v3

NVD

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.

CWE-347

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.34%probability of exploitation in 30 days

25thpercentile

Low risk: more likely to be exploited than 25% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-09.