CVE-2026-111805: Apache Traffic Server HTTP/2 request smuggling via truncated Content-Length

CVE-2026-111805 · Severity: high · CVSS 8.6 · Published 2026-10-21

Apache Traffic Server is a caching proxy that forwards HTTP requests to origin servers. A flaw in how it handles HTTP/2 requests with truncated Content-Length headers allows attackers to send malformed requests that exhaust the worker pool on HTTP/1.1 origin servers, causing denial of service and potential service outages.

Technologies: Apache Traffic Server. Vendors: Apache.

Quick answers

Is CVE-2026-111805 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-111805 being exploited in the wild.
How severe is CVE-2026-111805?
High severity, with a CVSS score of 8.6, published 21 October 2026.
Which products and versions are affected?
Apache Traffic Server 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, 10.2.0.
Is there a fix for CVE-2026-111805?
Yes: fixed in 9.2.16, 10.1.5, 10.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-111805 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-111805?
Check whether you run Apache Traffic Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Fixed in: 9.2.16, 10.1.5, 10.2.1

Technical details

The vulnerability arises from improper handling of truncated HTTP/2 Content-Length values when Traffic Server forwards requests to HTTP/1.1 origin servers. An attacker can craft HTTP/2 requests with malformed Content-Length headers that cause connections to origin servers to hang or consume resources abnormally, exhausting the origin's worker pool and leading to denial of service. The issue affects HTTP/2 to HTTP/1.1 protocol translation logic.

Affected products

  • Apache Traffic Server 8.0.0 through 8.1.11, 9.0.0 through 9.2.15, 10.0.0 through 10.1.4, 10.2.0

Timeline

  • 2026-10-21: disclosed

References

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