# CVE-2026-69217

## Summary

- **CVE ID:** CVE-2026-69217
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N)
- **CWE:** CWE-444
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 16, 2026

## Description

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive intermediary that selects a different occurrence, an unauthenticated attacker can create CL.CL request smuggling that bypasses front-end controls, captures a later user’s headers, or poisons a cache. The shared client parser can also misframe responses from a malicious or compromised upstream when the client acts as a proxy for multiple downstream consumers. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

## Affected Products

- http4s — http4s (< 0.23.35)
- http4s — http4s (>= 1.0.0-M1, < 1.0.0-M47)

## References

- [CNA](https://github.com/http4s/http4s/security/advisories/GHSA-p83c-4wj9-p6w9)
- [CNA](https://github.com/http4s/http4s/commit/24e8d34e3ea89f8f23e0053ec9944f6467e8086d)
- [CNA](https://github.com/http4s/http4s/releases/tag/v0.23.35)
- [CNA](https://github.com/http4s/http4s/releases/tag/v1.0.0-M47)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.50%
- **EPSS Percentile:** 41.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._