---
cve: "CVE-2026-28490"
severity: "HIGH"
cvss: 8.3
epss: "14%"
vendor: "authlib"
kev: false
exploited: false
published: "2026-03-16 18:16:07"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-15T00:37:11+02:00"
---

# CVE-2026-28490

> 8.3 HIGH · 🧪 PoC

## Beschreibung

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-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 9266eaa2227ad7e21dc731b2a4a01909aabd934b (Commit)
- 48b345f29f6c459f11c6a40162b6c0b742ef2e22 (Commit)

## Referenzen

- <https://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78>
- <https://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22>
- <https://github.com/authlib/authlib/releases/tag/v1.6.9>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-28490) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_