CVE-2026-28490

Publication date 16 March 2026

Last updated 16 July 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
python-authlib 26.04 LTS resolute
Fixed 1.6.7-1ubuntu0.1~esm1
25.10 questing Ignored end of life, was needs-triage
24.04 LTS noble
Fixed 1.3.0-1ubuntu0.1~esm2
22.04 LTS jammy
Fixed 0.15.5-1ubuntu0.1~esm2

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
python-authlib

Severity score breakdown

CVSS version:

Base score 8.3 · High

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

Base score 6.5 · Medium

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

References

Related Ubuntu Security Notices (USN)

Other references

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