{"id":"CVE-2026-47775","summary":"Envoy OAuth2 Filter: Padding Oracle via AES-256-CBC Cookie Decryption","details":"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.","aliases":["BIT-envoy-2026-47775","GHSA-396h-jpq4-vc7p"],"modified":"2026-07-08T08:13:38.761737543Z","published":"2026-06-26T17:23:51.663Z","related":["openSUSE-SU-2026:11141-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47775.json","cwe_ids":["CWE-209","CWE-327"],"cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47775.json"},{"type":"ADVISORY","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-396h-jpq4-vc7p"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47775"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/envoyproxy/envoy","events":[{"introduced":"84305a6cb64bd55aaf606bdd53de7cd6080427a1"},{"fixed":"f2a676793ef8c5ea9d1df9e1e806826c8f1fd51e"},{"introduced":"63ee0dc79dce88117c6bd2df5a742f8eb67ea980"},{"fixed":"ab5b508735aac42f2855099285de9c79258e5166"},{"introduced":"6d9bb7d9a85d616b220d1f8fe67b61f82bbdb8d3"},{"fixed":"89fee998e13fd53a26df1c492bc0f9bf0fabc5be"},{"introduced":"f1dd21b16c244bda00edfb5ffce577e12d0d2ec2"},{"fixed":"5022e0b6cadc236414e98c74d611c9566ca398b8"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.35.0"},{"fixed":"1.35.11"},{"introduced":"1.36.0"},{"fixed":"1.36.7"},{"introduced":"1.37.0"},{"fixed":"1.37.3"},{"introduced":"1.38.0"},{"fixed":"1.38.1"}]}}],"versions":["v1.38.0","v1.37.2","v1.36.6","v1.35.10","v1.37.1","v1.36.5","v1.35.9","v1.37.0","v1.36.4","v1.35.8","v1.36.3","v1.35.7","v1.35.6","v1.36.2","v1.36.1","v1.35.5","v1.36.0","v1.35.4","v1.35.3","v1.35.2","v1.35.1","v1.35.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47775.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"}]}