CVE-2026-59173 Apache Traffic Server: DoS vulnerability in HTTP/2 via stalled flow-control conditions

What is CVE-2026-59173?

CVE-2026-59173 is a high-severity denial of service vulnerability in Apache Traffic Server, published on 18 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Uncontrolled Resource Consumption vulnerability in Apache Traffic Server.

This issue affects Apache Traffic Server: from 9.0.0 through 9.1.13, from 10.0.0 through 10.1.2.

Users are recommended to upgrade to version 9.1.14 or 10.1.3, which fixes the issue.

Weakness: CWE-400

Which versions are affected by CVE-2026-59173?

It affects 1 product.

Products include Apache Traffic Server.

How do I fix CVE-2026-59173?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-59173 being exploited?

There is no known exploitation of CVE-2026-59173 in the wild and no public exploit code.

Other vulnerabilities in Apache Traffic Server

• CVE-2014-3525 Other in n/a Critical 10.0
• CVE-2021-43082 heap-buffer-overflow with stats-over-http plugin Critical 9.8
• CVE-2021-35474 Dynamic stack buffer overflow in cachekey plugin Critical 9.8
• CVE-2019-17559 Other in Apache Traffic Server Critical 9.8
• CVE-2019-17565 Other in Apache Traffic Server Critical 9.8

All Apache Traffic Server vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-59173, GHSA-6m23-f848-jcqf, UBUNTU-CVE-2026-59173.