High severity · published Jun 26, 2026
CVE-2026-47220
Envoy: Segmentation fault when using %REQUESTED_SERVER_NAME% in log format
7.5
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EN
envoy · envoyproxy
>= 1.38.0, < 1.38.3; >= 1.37.0, < 1.37.5 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-47220
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-47220
Exploit
https://github.com/envoyproxy/envoy/security/advisories/GHSA-j9wh-4qfm-wf2v
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-47220
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2493652
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47220.json
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