Review reviewHigh

CVE-2026-47220

envoyproxy envoy, OpenShift Service Mesh 2, OpenShift Service Mesh 3

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.

CVSS: 7.5
EPSS: 0.42%
CISA KEV: Not listed
Published: 2026.06.27

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.42%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: envoyproxy envoy, OpenShift Service Mesh 2, OpenShift Service Mesh 3
Affected versions: >= >= 1.38.0, < 1.38.3, >= >= 1.37.0, < 1.37.5, >= 1.37.0 < 1.37.5, >= 1.38.0 < 1.38.3
Fixed versions: 1.37.5, 1.38.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that envoyproxy envoy, OpenShift Service Mesh 2, OpenShift Service Mesh 3 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-476