CVE-2026-45232 Details

A stack memory corruption vulnerability has been identified in Rsync versions prior to 3.4.3. This off-by-one out-of-bounds write occurs in the establish_proxy_connection() function within socket.c. The vulnerability allows network attackers to manipulate stack memory by sending a malformed HTTP proxy response. Exploitation requires the RSYNC_PROXY environment variable to be set, tunneling the connection through an HTTP CONNECT proxy. The vulnerability can be exploited by a malicious proxy or a network attacker positioned between the client and the proxy, who sends a response line of 1023 or more bytes without a newline terminator. This causes a null byte to be written to an out-of-bounds stack address, potentially leading to corruption of adjacent stack data.

Users should upgrade to Rsync version 3.4.3 or later. If an immediate upgrade is not possible, do not set the RSYNC_PROXY environment variable or use only trusted HTTP proxies on secure networks.