CVE-2016-8740 Denial of service in Apache HTTP Server

What is CVE-2016-8740?

CVE-2016-8740 is a high-severity denial of service vulnerability in Apache Http Server, published on 5 Dec 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.

Weakness: CWE-399, CWE-20

Which versions are affected by CVE-2016-8740?

It affects 1 product.

Products include Apache Http Server.

How do I fix CVE-2016-8740?

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-2016-8740 being exploited?

There is no known exploitation of CVE-2016-8740 in the wild and no public exploit code.

Public exploit code: 1 Exploit-DB entry and 2 proofs of concept on GitHub.

Other vulnerabilities in Apache Http Server

• CVE-2021-42013 Apache HTTP Server Path Traversal Exploited Critical 9.8
• CVE-2024-38475 Apache HTTP Server Improper Escaping of Output Exploited Critical 9.1
• CVE-2021-40438 Apache HTTP Server-Side Request Forgery (SSRF) Exploited Critical 9.0
• CVE-2019-0211 Apache HTTP Server Privilege Escalation Exploited High 7.8
• CVE-2021-41773 Apache HTTP Server Path Traversal Exploited High 7.5

All Apache Http Server vulnerabilities

Sources

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

Also known as DEBIAN-CVE-2016-8740, GHSA-pfj2-72r3-p693, SUSE-SU-2017:0203-1.