# CVE-2026-43620: Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()

CVE-2026-43620 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.

- Web page: https://patchblox.com/security/cve/CVE-2026-43620
- Priority: Routine
- CVSS: 6.5 (Moderate)
- EPSS: 0.0043
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 19, 2026
- Weakness: Out-of-bounds Read
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | rsync Debian 12.15 (bookworm) | 3.2.7-1+deb12u5 | [DEBIAN-CVE-2026-43620](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43620.md) | May 27, 2026 |
| Linux | rsync Debian 13.5 (trixie) | 3.4.1+ds1-5+deb13u3 | [DEBIAN-CVE-2026-43620](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43620.md) | May 27, 2026 |
| Linux | rsync Debian 14 | 3.4.3+ds1-1 | [DEBIAN-CVE-2026-43620](https://patchblox.com/security/data/fix/linux/debian-cve-2026-43620.md) | May 27, 2026 |
| Linux | rsync Ubuntu 18.04.6 LTS (bionic) | 3.1.2-2.1ubuntu1.6+esm3 | [rsync 3.1.2-2.1ubuntu1.6+esm3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-rsync-3.1.2-2.1ubuntu1.6-esm3.md) | May 19, 2026 |
| Linux | rsync Ubuntu 20.04 LTS (focal) | 3.1.3-8ubuntu0.9+esm1 | [rsync 3.1.3-8ubuntu0.9+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-rsync-3.1.3-8ubuntu0.9-esm1.md) | May 19, 2026 |
| Linux | rsync Ubuntu 22.04.1 LTS (jammy) | 3.2.7-0ubuntu0.22.04.6 | [rsync 3.2.7-0ubuntu0.22.04.6](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-rsync-3.2.7-0ubuntu0.22.04.6.md) | May 27, 2026 |
| Linux | rsync Ubuntu 24.04.5 LTS (noble) | 3.2.7-1ubuntu1.4 | [rsync 3.2.7-1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-rsync-3.2.7-1ubuntu1.4.md) | May 27, 2026 |
| Linux | rsync Ubuntu 25.10 (questing) | 3.4.1+ds1-5ubuntu1.2 | [rsync 3.4.1+ds1-5ubuntu1.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-rsync-3.4.1-ds1-5ubuntu1.2.md) | May 27, 2026 |
| Linux | rsync Ubuntu 26.04.1 LTS (resolute) | 3.4.1+ds1-7ubuntu0.2 | [rsync 3.4.1+ds1-7ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-rsync-3.4.1-ds1-7ubuntu0.2.md) | May 19, 2026 |
| Linux | rsync amzn 2023 | 3.5.1-1.amzn2023.0.1 | [ALAS2023-2026-3131](https://patchblox.com/security/data/fix/linux/alas2023-2026-3131.md) | Sep 28, 2026 |
| Linux | rsync opensuse-leap 16.0 | 3.4.1-160000.6.1 | [OPENSUSE-SU-2026:21650-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21650-1.md) | Aug 26, 2026 |
| Linux | rsync sles 16.0 | 3.4.1-160000.6.1 | [SUSE-SU-2026:23323-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23323-1.md) | Aug 26, 2026 |
| Linux | rsync-daemon amzn 2023 | 3.5.1-1.amzn2023.0.1 | [ALAS2023-2026-3131](https://patchblox.com/security/data/fix/linux/alas2023-2026-3131.md) | Sep 28, 2026 |
| Linux | rsync-debuginfo amzn 2023 | 3.5.1-1.amzn2023.0.1 | [ALAS2023-2026-3131](https://patchblox.com/security/data/fix/linux/alas2023-2026-3131.md) | Sep 28, 2026 |
| Linux | rsync-debugsource amzn 2023 | 3.5.1-1.amzn2023.0.1 | [ALAS2023-2026-3131](https://patchblox.com/security/data/fix/linux/alas2023-2026-3131.md) | Sep 28, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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