Undisclosed Patch Vulnerability Caused HTTP2Shell via If-Statement

A vulnerability in an undisclosed patch led to the HTTP2Shell issue through an if-statement. The vulnerability is related to a stale table read in the Brotli compression algorithm. Further information about the issue can be found in an article and discussion on the topic. The article provides details on the Brotli stale table read, while the discussion is hosted on a news site. The vulnerability and its cause are the subject of a blog post and comments section. The issue is being discussed online with currently no comments provided.