Published: 10 June 2021
Apache HTTP Server versions 2.4.6 to 2.4.46 mod_proxy_wstunnel configured on an URL that is not necessarily Upgraded by the origin server was tunneling the whole connection regardless, thus allowing for subsequent requests on the same connection to pass through with no HTTP validation, authentication or authorization possibly configured.
CVSS 3 base score: 5.3
The patches required to fix this in stable releases are quite intrusive and change behaviour. It may not make sense to backport them to stable releases.