Vulnerability · Published May 20, 2026 · Assigned by VulnCheck
CVE-2026-43620Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()
Medium 6.5
In plain English
A medium-severity out-of-bounds read in rsync from RsyncProject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-43620 |
| Alpine:v3.21 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-43620 |
| Alpine:v3.22 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-43620 |
| Alpine:v3.23 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-43620 |
| Alpine:v3.24 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-43620 |
| Debian:12 | rsync | 3.2.7-1+deb12u5 | DEBIAN-CVE-2026-43620 |
| Debian:13 | rsync | 3.4.1+ds1-5+deb13u3 | DEBIAN-CVE-2026-43620 |
| Debian:14 | rsync | 3.4.3+ds1-1 | DEBIAN-CVE-2026-43620 |
| Ubuntu:22.04:LTS | rsync | 3.2.7-0ubuntu0.22.04.6 | UBUNTU-CVE-2026-43620 |
| Ubuntu:24.04:LTS | rsync | 3.2.7-1ubuntu1.4 | UBUNTU-CVE-2026-43620 |
| Ubuntu:25.10 | rsync | 3.4.1+ds1-5ubuntu1.2 | UBUNTU-CVE-2026-43620 |
| Ubuntu:26.04:LTS | rsync | 3.4.1+ds1-7ubuntu0.2 | UBUNTU-CVE-2026-43620 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RsyncProject | rsync | 0 – before 3.4.3 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H