---
cve: "CVE-2026-47775"
severity: "MEDIUM"
cvss: 6.8
epss: "0.2%"
vendor: "envoyproxy"
kev: false
exploited: false
published: "2026-06-26 18:16:59"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-22T09:53:56+02:00"
---

# CVE-2026-47775

> 6.8 MEDIUM · 🧪 PoC

## Beschreibung

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, the OAuth2 HTTP filter's encrypt()/decrypt() functions use AES-256-CBC without an authentication tag (no HMAC, no AEAD). The /callback endpoint returns HTTP 302 on successful decryption and HTTP 401 on padding failure, creating a padding oracle. An attacker who obtains the encrypted CodeVerifier cookie can recover the plaintext PKCE code_verifier in ~6,200 requests (~100 seconds), then exchange it with a stolen authorization code to obtain the victim's access token. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Erforderlich | good |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- f2a676793ef8c5ea9d1df9e1e806826c8f1fd51e (Commit)
- ab5b508735aac42f2855099285de9c79258e5166 (Commit)

## Referenzen

- <https://github.com/envoyproxy/envoy/security/advisories/GHSA-396h-jpq4-vc7p>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-47775) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_