RsyncProject rsync up to 3.4.2 Access Control List authentication by alternate name

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability was found in RsyncProject rsync up to 3.4.2. It has been rated as problematic. Affected by this issue is some unknown functionality of the component Access Control List Handler. The manipulation leads to authentication by alternate name. This vulnerability is referenced as CVE-2026-43617. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in RsyncProject rsync up to 3.4.2. It has been rated as problematic. This issue affects an unknown function of the component Access Control List Handler. The manipulation with an unknown input leads to a authentication by alternate name vulnerability. Using CWE to declare the problem leads to CWE-289. The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was published by Joshua Rogers as GHSA-rjfm-3w2m-jf4f. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-43617 since 05/01/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 315780 (Debian dla-4591 : rsync - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.4.3 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the databases at CNNVD (CNNVD-202605-4470), Tenable (315780) and CERT Bund (WID-SEC-2026-1611). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Debian Linux
  • Fedora Linux
  • Ubuntu Linux
  • SUSE Linux
  • Open Source Rsync
  • SUSE openSUSE

Productinfo

Type

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.2
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.8
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authentication by alternate name
CWE: CWE-289 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 315780
Nessus Name: Debian dla-4591 : rsync - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: rsync 3.4.3

Timelineinfo

05/01/2026 CVE reserved
05/20/2026 +19 days Advisory disclosed
05/20/2026 +0 days VulDB entry created
06/02/2026 +12 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-rjfm-3w2m-jf4f
Researcher: Joshua Rogers
Status: Confirmed

CVE: CVE-2026-43617 (🔒)
GCVE (CVE): GCVE-0-2026-43617
GCVE (VulDB): GCVE-100-364805
CERT Bund: WID-SEC-2026-1611 - Rsync: Mehrere Schwachstellen
CNNVD: CNNVD-202605-4470 - Rsync 安全漏洞

Entryinfo

Created: 05/20/2026 08:30
Updated: 06/02/2026 01:07
Changes: 05/20/2026 08:30 (79), 05/20/2026 19:32 (7), 05/21/2026 17:13 (2), 05/21/2026 21:01 (6), 05/26/2026 20:16 (1), 06/02/2026 01:07 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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