CVE-2026-43620: rsyncproject rsync Out-of-bounds Read

Vulnerability summary

CVE-2026-43620 is a medium (CVSS 6.9) Out-of-bounds Read vulnerability in rsyncproject rsync. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.6% of scored vulnerabilities.

Timeline

1. 20-05-2026
   PublishedVulnerability first disclosed.
2. 14-07-2026
   Last modifiedVulnerability information updated.

Description

Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in recv_files() in receiver.c that allows a malicious rsync server to crash the rsync client process. Attackers can exploit the vulnerability by setting CF_INC_RECURSE 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 ITEM_TRANSFER, 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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.