---
title: "CVE-2026-111809: Apache Traffic Server - HTTP Request Smuggling"
description: "Apache Traffic Server 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0 contains an HTTP request smuggling vulnerability caused by improper handling of HEAD requests with Content-Length or Transfer-Encoding headers, letting remote attackers smuggle requests, exploit requires crafted HEAD requests."
url: https://panop.io/threat-heartbeat/CVE-2026-111809/
---

# CVE-2026-111809 Apache Traffic Server - HTTP Request Smuggling

Apache Traffic Server 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, and 10.2.0 contains an HTTP request smuggling vulnerability caused by improper handling of HEAD requests with Content-Length or Transfer-Encoding headers, letting remote attackers smuggle requests, exploit requires crafted HEAD requests.

CVSS base score 9.3 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-111809)

## Details

Type

HTTP Request Smuggling

Impact

HTTP Request Smuggling

CVSS vector

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

Published

21 October 2026

Updated

22 October 2026

Weakness

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

## Vendor fix

Upgrade to versions 9.2.16, 10.1.5, or 10.2.1.

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-2026-111809](https://nvd.nist.gov/vuln/detail/CVE-2026-111809)
- [https://lists.apache.org/thread/r95dq29ywcd1f4x30snxlqmb12z4s4kc](https://lists.apache.org/thread/r95dq29ywcd1f4x30snxlqmb12z4s4kc)

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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

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