CVE-2023-43622

A flaw was found in the mod_http2 module of httpd. This flaw allows an attacker opening an HTTP/2 connection with an initial window size of 0 to block handling of that connection indefinitely. This vulnerability can exhaust worker resources in the server, similar to the well-known "slow loris" attack pattern.

This flaw only affects configurations with mod_http2 loaded and being used. Also, if there is no HTTP2 server configured, the httpd server is not affected and no further mitigation is needed.

The httpd mod_http2 module is enabled by default on Red Hat Enterprise Linux 8 and 9 via the mod_http2 package. However, there is no HTTP2 server configured by default.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.