Is CVE-2026-28490 in the CISA KEV catalog?

No. CVE-2026-28490 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-28490?

CVE-2026-28490 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2026-28490?

CVE-2026-28490 has an EPSS score of 0.14% (4th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-28490?

Upgrade python-authlib on debian 11 to 0.15.4-1+deb11u2 or later.

CVE & CISA-KEV Catalog

CVE-2026-28490

MEDIUM

6.5

CVSS v3

NVD

Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Python library concerning the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. Authlib registers RSA1_5 in its default algorithm registry without requiring explicit opt-in, and actively destroys the constant-time Bleichenbacher mitigation that the underlying cryptography library implements correctly. This issue has been patched in version 1.6.9.

CWE-203 CWE-327

How to fix

Remediation Available

python-authlibDebian

Fixed in:0.15.4-1+deb11u2CVE-2026-28490

Fixed in:1.6.9-1CVE-2026-28490

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.14%probability of exploitation in 30 days

4thpercentile

Low risk: more likely to be exploited than 4% of all known CVEs.

References

Patch1

github.com

Exploit1

github.com

Release Notes1

github.com

Embed a live status badge for CVE-2026-28490

Markdown

[![CVE-2026-28490](https://tridentstack.com/cve/badge/CVE-2026-28490.svg)](https://tridentstack.com/cve/CVE-2026-28490)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-28490"><img src="https://tridentstack.com/cve/badge/CVE-2026-28490.svg" alt="CVE-2026-28490"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

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 2026-03-17.