CVE-2023-39325

A flaw was found in handling multiplexed streams in the HTTP/2 protocol. A client can repeatedly make a request for a new multiplex stream and immediately send an RST_STREAM frame to cancel it. This creates extra work for the server setting up and tearing down the streams while not hitting any server-side limit for the maximum number of active streams per connection, resulting in a denial of service due to server resource consumption. Red Hat has rated the severity of this flaw as 'Important' as the US Cybersecurity and Infrastructure Security Agency (CISA) declared this vulnerability an active exploit.

CVE-2023-39325 was assigned for the Rapid Reset Attack in the Go language packages.

This CVE is related to CVE-2023-44487.

The majority of RHEL utilities are not long-running applications; instead, they are command-line tools. These tools utilize Golang package as build-time dependency, which is why they are classified as having a "Moderate" level of impact.

As go-lang vendors its dependencies, a package may contain a library with a known vulnerability, solely because of lower tier libraries including it as a part of its dependencies, but the vulnerable code is not reachable at runtime. In such cases the issue is not exploitable. We classify these situations as “Not affected” or “Will not fix,” depending on the risk of breaking other unrelated packages.

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.

The default stream concurrency limit in golang is 250 streams (requests) per HTTP/2 connection. This value may be adjusted in the golang.org/x/net/http2 package using the Server.MaxConcurrentStreams setting and the ConfigureServer function which are available in golang.org/x/net/http2.