CVE-2026-47775
Description
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.
How to fix
- envoyproxy envoy1.35.11, 1.36.7, 1.37.3, 1.38.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| envoyproxy envoy | 1.35.0 ≤ v < 1.35.11, 1.36.0 ≤ v < 1.36.7, 1.37.0 ≤ v < 1.37.3, 1.38.0 ≤ v < 1.38.1 | 1.35.11, 1.36.7, 1.37.3, 1.38.1 |
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