When NGINX Plus or NGINX OSS are configured to use the HTTP/3 QUIC module, undisclosed HTTP/3 requests can cause NGINX worker processes to terminate or cause other potential impact. This attack requires that a request be specifically timed during the connection draining process, which the attacker has no visibility and limited influence over.
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
The product writes data past the end, or before the beginning, of the intended buffer.