CVEvulnerability

CVE-2025-64763

5.3 MEDIUM Published 2025-12-03 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2025-12-03
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
3.7 LOW — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 3.1 ([email protected])
5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weaknesses
CWE-693

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.

Affected configurations

• envoyproxy envoy (< 1.33.13) • envoyproxy envoy (>= 1.34.0 < 1.34.11) • envoyproxy envoy (>= 1.35.0 < 1.35.7) • envoyproxy envoy (>= 1.36.0 < 1.36.3)

Related

Weakness · CWE (1)

  • CWE-693 Protection Mechanism Failure weakness

References