Upstream information

CVE-2026-73548 at MITRE

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete HTTP/1.1 request in extended CONNECT data; Envoy downgrades the request, writes the data unframed to a keep-alive HTTP/1.1 upstream, and returns the socket to the shared pool while the smuggled response remains queued. A different downstream client can then receive the attacker's response. The relevant scope boundary is that webSocket upgrades, plain CONNECT, disabled backend keep-alive, per-downstream pools, and max_requests_per_connection set to 1 are not affected by the demonstrated path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

SUSE information

Overall state of this security issue: Does not affect SUSE products

No SUSE Bugzilla entries cross referenced.

No SUSE Security Announcements cross referenced.

List of released packages

Product(s) Fixed package version(s) References
openSUSE Tumbleweed
  • istioctl >= 1.30.4-1.1
  • istioctl-bash-completion >= 1.30.4-1.1
  • istioctl-zsh-completion >= 1.30.4-1.1
 Patchnames:
openSUSE-Tumbleweed-2026-11630

SUSE Timeline for this CVE

CVE page created: Sat Aug 29 13:13:25 2026
CVE page last modified: Tue Sep 22 11:44:09 2026