Rsync < 3.4.3 Authorization Bypass via Hostname Resolution
CVE-2026-43617 is fixed in 4 products on 1 platform, first by rsync 3.1.2-2.1ubuntu1.6+esm3, released May 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.
Rsync version 3.4.2 and prior contain an authorization bypass vulnerability in the rsync daemon's hostname-based access control list enforcement when configured with chroot. Attackers can bypass hostname-based deny rules by controlling the PTR record for their source IP address, allowing connections from hostnames that administrators intended to deny when reverse DNS resolution fails and defaults to UNKNOWN.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| rsync · Debian 12.15 (bookworm) | 3.2.7-1+deb12u5 | DEBIAN-CVE-2026-43617 | May 27, 2026 |
| rsync · Debian 13.5 (trixie) | 3.4.1+ds1-5+deb13u3 | DEBIAN-CVE-2026-43617 | May 27, 2026 |
| rsync · Debian 14 | 3.4.3+ds1-1 | DEBIAN-CVE-2026-43617 | May 27, 2026 |
| rsync · Ubuntu 18.04.6 LTS (bionic) | 3.1.2-2.1ubuntu1.6+esm3 | rsync 3.1.2-2.1ubuntu1.6+esm3 | May 19, 2026 |
| rsync · Ubuntu 20.04 LTS (focal) | 3.1.3-8ubuntu0.9+esm1 | rsync 3.1.3-8ubuntu0.9+esm1 | May 19, 2026 |
| rsync · Ubuntu 22.04.1 LTS (jammy) | 3.2.7-0ubuntu0.22.04.6 | rsync 3.2.7-0ubuntu0.22.04.6 | May 27, 2026 |
| rsync · Ubuntu 24.04.5 LTS (noble) | 3.2.7-1ubuntu1.4 | rsync 3.2.7-1ubuntu1.4 | May 27, 2026 |
| rsync · Ubuntu 25.10 (questing) | 3.4.1+ds1-5ubuntu1.2 | rsync 3.4.1+ds1-5ubuntu1.2 | May 27, 2026 |
| rsync · Ubuntu 26.04.1 LTS (resolute) | 3.4.1+ds1-7ubuntu0.2 | rsync 3.4.1+ds1-7ubuntu0.2 | May 19, 2026 |
| rsync · amzn 2023 | 3.5.1-1.amzn2023.0.1 | ALAS2023-2026-3131 | Sep 28, 2026 |
| rsync · opensuse-leap 16.0 | 3.4.1-160000.6.1 | OPENSUSE-SU-2026:21650-1 | Aug 26, 2026 |
| rsync · sles 16.0 | 3.4.1-160000.6.1 | SUSE-SU-2026:23323-1 | Aug 26, 2026 |
| rsync-daemon · amzn 2023 | 3.5.1-1.amzn2023.0.1 | ALAS2023-2026-3131 | Sep 28, 2026 |
| rsync-debuginfo · amzn 2023 | 3.5.1-1.amzn2023.0.1 | ALAS2023-2026-3131 | Sep 28, 2026 |
| rsync-debugsource · amzn 2023 | 3.5.1-1.amzn2023.0.1 | ALAS2023-2026-3131 | Sep 28, 2026 |
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