Out-of-bounds Read in Rsyncproject Rsync
CVE-2026-43620
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (37.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000
Affected products
- Rsyncproject Rsync — versions 0
- Samba Rsync
Weakness classification (CWE)
References
- github.com/RsyncProject/rsync/security/advisories/GHSA-28pw-r563-rxvm (vendor-advisory, Vendor Advisory)
- github.com/RsyncProject/rsync/releases/tag/v3.4.3 (release-notes, Release Notes)
- www.vulncheck.com/advisories/rsync-out-of-bounds-array-read-via-recv-files (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-43620?
- CVE-2026-43620 is a medium-severity vulnerability in Rsyncproject Rsync, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2026-05-20.
- How severe is CVE-2026-43620?
- Medium severity. CVSS v3 base score is 6.5 out of 10.