# CVE-2026-47220: Envoy: Segmentation fault when using %REQUESTED_SERVER_NAME% in log format

> Attackers can crash Envoy proxy by sending requests with missing host headers when specific log format options are enabled.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2026
- **Updated:** 15 Jul 2026
- **Also known as:** BIT-envoy-2026-47220, GHSA-j9wh-4qfm-wf2v

## What is CVE-2026-47220?

CVE-2026-47220 is a high-severity vulnerability in Envoyproxy Envoy, published on 26 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-47220?

1 open source package ship an affected version, including envoy. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | From 1.37.0 | 1.37.5, 1.38.3 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2026-47220?

Upgrade envoy to a fixed version for your release line: 1.37.5 or 1.38.3.

## Is CVE-2026-47220 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47220 exists.

## Other vulnerabilities in Envoyproxy Envoy

- [CVE-2022-29226](https://insights.sbomify.com/CVE-2022-29226/): Trivial authentication bypass in Envoy (critical 10.0)
- [CVE-2019-18801](https://insights.sbomify.com/CVE-2019-18801/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-18802](https://insights.sbomify.com/CVE-2019-18802/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-35470](https://insights.sbomify.com/CVE-2020-35470/): Information disclosure in n/a (high 8.8)
- [CVE-2024-23324](https://insights.sbomify.com/CVE-2024-23324/): Envoy ext auth can be bypassed when Proxy protocol filter sets invalid UTF-8 metadata (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47220 and fix it if it is affected.

What it is: CVE-2026-47220 is a high-severity vulnerability in Envoyproxy Envoy, published on 26 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-47220 exists.

Affected packages and fixed versions:
- envoy (Bitnami): affected from 1.37.0; fixed in 1.37.5, 1.38.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-47220/ (Markdown: https://insights.sbomify.com/CVE-2026-47220/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47220
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47220
- OSV: https://osv.dev/vulnerability/CVE-2026-47220

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47220/
Summaries are generated and may contain mistakes; the official description above is the record.