CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NCVE-2025-64763
Medium (5.3) in envoyproxy envoy. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in github.com/envoyproxy/envoy 1.33.13, 1.34.11, 1.35.7.
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.
Severity
- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 22% of CVEs (scores of 2026-10-31)
- CWE
- CWE-693
- Published
- Modified
- Record from
- the NVD, synced
Affected
- envoyproxy:envoy
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-rj35-4m94-77jh | Go | github.com/envoyproxy/envoy | >=1.36.0 <1.36.3 | 1.36.3 |
| GHSA-rj35-4m94-77jh | Go | github.com/envoyproxy/envoy | >=1.35.0 <1.35.7 | 1.35.7 |
| GHSA-rj35-4m94-77jh | Go | github.com/envoyproxy/envoy | >=1.34.0 <1.34.11 | 1.34.11 |
| GHSA-rj35-4m94-77jh | Go | github.com/envoyproxy/envoy | <1.33.13 | 1.33.13 |