CVE-2025-64763
Dec. 4, 2025, 5:15 p.m.
3.7
Low
Description
Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONNECT tunnel state. By default Envoy continues to allow early CONNECT data to avoid disrupting existing deployments. The envoy.reloadable_features.reject_early_connect_data runtime flag can be set to reject CONNECT requests that send data before a 2xx response when intermediaries upstream from Envoy may reject establishment of a CONNECT tunnel.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Envoy Proxy |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-693
Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | envoy_proxy | envoy | 1.33.12 | / | / | / | / | / | / | / |
| a | envoy_proxy | envoy | 1.34.10 | / | / | / | / | / | / | / |
| a | envoy_proxy | envoy | 1.35.6 | / | / | / | / | / | / | / |
| a | envoy_proxy | envoy | 1.36.2 | / | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: HIGH
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: LOW
- Integrity Impact: NONE
- Availability Impact: NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Timeline
Published: Dec. 3, 2025, 6:15 p.m.
Last Modified: Dec. 4, 2025, 5:15 p.m.
Last Modified: Dec. 4, 2025, 5:15 p.m.
Status : Undergoing Analysis
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
security-advisories@github.com
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.