---
title: "CVE-2026-69205: Http4s - Server Side Request Forgery"
description: "Http4s prior to 0.23.35 and 1.0.0-M47 contains a server-side request forgery caused by case-sensitive substring test and improper charset decoding in Ember's HeaderP.parse, letting attackers perform request smuggling and cache poisoning, exploit requires crafted HTTP requests."
url: https://panop.io/threat-heartbeat/CVE-2026-69205/
---

# CVE-2026-69205 Http4s - Server Side Request Forgery

Http4s prior to 0.23.35 and 1.0.0-M47 contains a server-side request forgery caused by case-sensitive substring test and improper charset decoding in Ember's HeaderP.parse, letting attackers perform request smuggling and cache poisoning, exploit requires crafted HTTP requests.

CVSS base score 8.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.48% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-69205)

## Details

Type

Server Side Request Forgery

Impact

Server Side Request Forgery

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Published

15 September 2026

Updated

15 October 2026

Weakness

[CWE-444](https://cwe.mitre.org/data/definitions/444.html)

## Vendor fix

Upgrade to versions 0.23.35 or 1.0.0-M47 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-69205](https://nvd.nist.gov/vuln/detail/CVE-2026-69205)
- [https://github.com/http4s/http4s/releases/tag/v1.0.0-M47](https://github.com/http4s/http4s/releases/tag/v1.0.0-M47)
- [https://github.com/http4s/http4s/security/advisories/GHSA-9998-894r-fwvr](https://github.com/http4s/http4s/security/advisories/GHSA-9998-894r-fwvr)
- [https://github.com/http4s/http4s/commit/5e88b2e7b4e6ea2f0c61040a4bc9de0d73e51217](https://github.com/http4s/http4s/commit/5e88b2e7b4e6ea2f0c61040a4bc9de0d73e51217)
- [https://github.com/http4s/http4s/releases/tag/v0.23.35](https://github.com/http4s/http4s/releases/tag/v0.23.35)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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