CVE-2026-47775: envoyproxy envoy

Vulnerability summary

CVE-2026-47775 is a medium (CVSS 6.8) vulnerability in envoyproxy envoy. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 11.7% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 26-06-2026
   PublishedVulnerability first disclosed.
2. 29-06-2026
   Last modifiedVulnerability information updated.

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.

• CWE-209Generation of Error Message Containing Sensitive InformationThe product generates an error message that includes sensitive information about its environment, users, or associated data.
• CWE-327Use of a Broken or Risky Cryptographic AlgorithmThe product uses a broken or risky cryptographic algorithm or protocol.