When NGINX Plus or NGINX OSS are configured to use the HTTP/3 QUIC module and the network infrastructure supports a Maximum Transmission Unit (MTU) of 4096 or greater without fragmentation, undisclosed QUIC packets can cause NGINX worker processes to leak previously freed memory.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.