CVE-2026-47220
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.66%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.66% probability · 50th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- envoyproxy/envoy
- Source
- security-advisories@github.com
References
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-j9wh-4qfm-wf2vExploit, Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-47220
- https://bugzilla.redhat.com/show_bug.cgi?id=2493652
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-j9wh-4qfm-wf2vExploit, Vendor Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47220.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.