---
title: "CVE-2026-111816: Apache Traffic Server - HTTP Request Smuggling"
description: "Apache Traffic Server 8.0.0 to 8.1.11, 9.0.0 to 9.2.15, 10.0.0 to 10.1.4, and 10.2.0 contains a cache poisoning and response-framing desync vulnerability caused by malformed 302 response with Transfer-Encoding: chunked bypassing parse error rejection, letting attackers poison cache, exploit requires sending malformed HTTP responses."
url: https://panop.io/threat-heartbeat/CVE-2026-111816/
---

# CVE-2026-111816 Apache Traffic Server - HTTP Request Smuggling

Apache Traffic Server 8.0.0 to 8.1.11, 9.0.0 to 9.2.15, 10.0.0 to 10.1.4, and 10.2.0 contains a cache poisoning and response-framing desync vulnerability caused by malformed 302 response with Transfer-Encoding: chunked bypassing parse error rejection, letting attackers poison cache, exploit requires sending malformed HTTP responses.

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-2026-111816)

## Details

Type

HTTP Request Smuggling

Impact

Data Tampering

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 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-2026-111816](https://nvd.nist.gov/vuln/detail/CVE-2026-111816)
- [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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