Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in...

Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in recvfiles() in receiver.c that allows a malicious rsync server to crash the rsync client process. Attackers can exploit the vulnerability by setting CFINCRECURSE in compatibility flags and sending a specially crafted file list where the first sorted entry is not the leading dot directory, followed by a transfer record with ndx=0 and an iflag word without ITEMTRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference an invalid pointer at an unmapped address, resulting in a deterministic SIGSEGV crash of the rsync client.