CVE-2026-47775
MEDIUMDescription
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
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 12% of all known CVEs.
References
Related Vulnerabilities
Other CWE-209 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-29059 | High | 7.5 | 99% | KEV | - |
| CVE-2021-22145 | Medium | 6.5 | 76% | - | - |
| CVE-2010-3332 | Medium | 6.4 | 67% | - | - |
| CVE-2025-62168 | Critical | 10.0 | 63% | - | Fix |
| CVE-2025-47813 | Medium | 4.3 | 59% | KEV | Fix |
| CVE-2013-7331 | Medium | 6.5 | 58% | KEV | - |
Common questions
How do I fix CVE-2026-47775?
Upgrade envoy to 1.38.1 or later.
Is CVE-2026-47775 being actively exploited?
Not that we know of. CVE-2026-47775 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.22% is the estimated probability that it will be exploited in the next 30 days. That is higher than 12% of all scored CVEs.
How severe is CVE-2026-47775?
CVE-2026-47775 has a CVSS v3 base score of 6.8, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-47775 affect?
Published advisories record a fix for envoy (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-47775
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-29.