CVE-2020-11993 Race condition in Apache HTTP Server

What is CVE-2020-11993?

CVE-2020-11993 is a high-severity vulnerability in Apache Http Server, published on 7 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and on certain traffic edge patterns, logging statements were made on the wrong connection, causing concurrent use of memory pools. Configuring the LogLevel of mod_http2 above "info" will mitigate this vulnerability for unpatched servers.

Weakness: CWE-444

Which versions are affected by CVE-2020-11993?

1 open source package ship an affected version, including apache. It affects 13 products.

Products include Apache Http Server, Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Netapp Clustered Data Ontap, Opensuse Leap and 7 more.

How do I fix CVE-2020-11993?

Upgrade apache to 2.4.44 or later.

Is CVE-2020-11993 being exploited?

There is no known exploitation of CVE-2020-11993 in the wild and no public exploit code.

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 ALPINE-CVE-2020-11993, BIT-apache-2020-11993, CLEANSTART-2026-OA42005, DEBIAN-CVE-2020-11993, GHSA-89mq-r3q6-9q3q, UBUNTU-CVE-2020-11993.