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Vulnerability record · CVE-2026-43617 · published 20 May 2026

CVE-2026-43617: Samba rsync vulnerability

Samba · Rsync

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.

6.3 CVSS 4.0 Medium EPSS 0.32% · top 77.5% CWE-289 · CWE-289
6.3CVSS 4.0 base score
0.32%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
24 Jul 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 Release Notes
https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjfm-3w2m-jf4f Vendor Advisory
https://www.vulncheck.com/advisories/rsync-authorization-bypass-via-hostname-resolution Third Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-43617), CISA KEV, FIRST EPSS (scores of 2026-10-09). This page is refreshed as NVD updates the record.