CVE-2026-47220: Envoy is an open source edge and service proxy designed for cloud-native applications

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-47220 is a high-severity flaw (CVSS 7.5) affecting envoy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-06-26
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: envoyproxy

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-26 19:16 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

envoyproxy envoy UPGRADE

Affected: >= 1.37.0 and < 1.37.5 · >= 1.38.0 and < 1.38.3

Fixed in: 1.37.5, 1.38.3

Safe to downgrade to: a release before 1.37.0

1. Check installed version

apt-cache policy envoy || rpm -q envoy || envoy --version

2. UPGRADE to 1.37.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade envoy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade envoy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.37.0 (Debian / Ubuntu)

apt-cache madison envoy sudo apt install envoy=<VERSION_BEFORE_1.37.0> sudo apt-mark hold envoy

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list envoy sudo dnf downgrade envoy-<VERSION_BEFORE_1.37.0> sudo dnf versionlock add envoy

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-47220?

envoy: upgrade to 1.37.5, 1.38.3. Exact commands for each OS are on this page.

Is CVE-2026-47220 being exploited?

CVE-2026-47220 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-47220 affect?

CVE-2026-47220 affects envoy. Severity is high (CVSS 7.5). 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,

How urgent is CVE-2026-47220?

Priority 49/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Envoy vulnerabilities

Related CVEs

CVE-2026-48042 HIGH 7.5 UPGRADE Envoy is an open source edge and service proxy designed for cloud-native applications
CVE-2026-48044 HIGH 7.5 UPGRADE Envoy is an open source edge and service proxy designed for cloud-native applications
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CVE-2026-48090 MEDIUM 5.9 UPGRADE Envoy is an open source edge and service proxy designed for cloud-native applications
CVE-2026-47221 MEDIUM 5.9 UPGRADE Envoy is an open source edge and service proxy designed for cloud-native applications

References

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