Out-of-bounds Read Affecting rsync package, versions <3.4.3-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.43% (35th percentile)

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  • Snyk IDSNYK-ALPINE321-RSYNC-16780681
  • published21 May 2026
  • disclosed20 May 2026

Introduced: 20 May 2026

CVE-2026-43620  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Alpine:3.21 rsync to version 3.4.3-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rsync package and not the rsync package as distributed by Alpine. See How to fix? for Alpine:3.21 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1