CVE-2026-43620

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.

How to fix CVE-2026-43620

To remediate CVE-2026-43620, upgrade the affected package to a fixed version below.

• —upgrade to 3.4.3-r0 or later
• —upgrade to 3.2.3-4+deb11u4 or later

Is CVE-2026-43620 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 3.4.3-r0
• from 0, < 3.2.3-4+deb11u4

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2026-43620
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-43620