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CVE-2026-47220highCWE-476

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

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.4%
exploitation probability
0.4%top 65% of all CVEs
observed exploitation
nono source reports it
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
envoyproxy · envoy