CVE-2026-47220

HIGH

Envoy: Segmentation fault when using %REQUESTED_SERVER_NAME% in log format

Title source: cna

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.37.0 until 1.37.5 and 1.38.3, when the %REQUESTED_SERVER_NAME(X:Y)% is used in log format and host related options is specified, like HOST_FIRST, SNI_FIRST, it's possible to crash Envoy when the specified host header is missing in the request headers. This vulnerability is fixed in 1.37.5 and 1.38.3.

References (4)

Core 4

Core References

Vendor Advisory

https://access.redhat.com/security/cve/CVE-2026-47220

Vendor Advisory

https://bugzilla.redhat.com/show_bug.cgi?id=2493652

Vendor Advisory

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47220.json

X_Refsource_Confirm x_refsource_confirm

https://github.com/envoyproxy/envoy/security/advisories/GHSA-j9wh-4qfm-wf2v

Scores

CVSS v3 7.5

EPSS 0.0042

EPSS Percentile 34.9%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment

Exploitation poc

Automatable yes

Technical Impact partial

Details

CWE

CWE-476

Status published

Products (3)

envoyproxy/envoy 1.37.0 - 1.37.5

envoyproxy/envoy >= 1.37.0, < 1.37.5

envoyproxy/envoy >= 1.38.0, < 1.38.3

Published Jun 26, 2026

Tracked Since Jun 27, 2026