Envoy forwards early CONNECT data in TCP proxy mode
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.36.3, 1.35.7, 1.34.11, 1.33.13
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- envoyproxy envoy
From 1.36.0 · through 1.36.2; From 1.35.0 · through 1.35.6; From 1.34.0 · through 1.34.10; through 1.33.12
- github.com/envoyproxy/envoyGo
From 1.36.0 · fixed in 1.36.3
- github.com/envoyproxy/envoyGo
From 1.35.0 · fixed in 1.35.7
- github.com/envoyproxy/envoyGo
From 1.34.0 · fixed in 1.34.11
- github.com/envoyproxy/envoyGo
fixed in 1.33.13