CVE-2026-43620: Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()
Last updated 2 June 2026
Other sources
Rsync < 3.4.3 Out-of-Bounds Array Read via recvfiles()
— Microsoft
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.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/rsyncto a version that resolves this vulnerability.Fixed in 3.2.3-4+deb11u4Fixed in 3.2.7-1+deb12u5Fixed in 3.4.1+ds1-5+deb13u3Fixed in 3.4.3+ds1-2 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43620?
CVE-2026-43620 is classified as a critical vulnerability due to its potential to crash the rsync client process.
How do I fix CVE-2026-43620?
To fix CVE-2026-43620, upgrade to rsync version 3.4.3 or later.
What types of systems are affected by CVE-2026-43620?
CVE-2026-43620 affects rsync versions prior to 3.4.3, impacting any system using those versions.
Can CVE-2026-43620 be exploited remotely?
Yes, a malicious rsync server can exploit CVE-2026-43620 to crash the rsync client remotely.
What is the impact of CVE-2026-43620?
The impact of CVE-2026-43620 is primarily the potential denial of service for the rsync client due to an out-of-bounds read.