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CVE-2026-28490

Authlib Vulnerable to JWE RSA1_5 Bleichenbacher Padding Oracle

Published: Mar 16, 2026Updated: Mar 17, 2026 Sources: CVE List NVD GHSA BDUCWE-203
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.1%
Top 96.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:LIntegrity
Low
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-203CWE-327

Affected Products

authlibauthlib
Library
OSS Libraries / generic-library
Red Hat QuayRed Hat Inc.
On-premWeb App
DevTools & CI / artifact-registry
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
РЕД ОСООО «Ред Софт»
On-premOS
Operating Systems / linux-distro
Red Hat SatelliteRed Hat Inc.
On-prem
Operating Systems
authliboss-projectOSS Librariesaka jose rfc
red hat inc.commercialUSOperating Systemsaka red hat
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
ооо «ред софт»commercialRUOperating Systemsaka red soft
and 5 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

2 techniques
Collection
Discovery
View detailed technique mapping

References

https://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78
github.com
https://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22
github.com
https://github.com/authlib/authlib/releases/tag/v1.6.9
github.com
and 9 more references View all →

Timeline

Published
Mar 16, 2026
Last Updated
Mar 17, 2026

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