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Vulnerabilities

Vulnerability · CVE-2026-43617

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.

Published May 20, 2026 · catalog updated Jul 24, 2026 · Rsync version 3.4.2 and

Check if you run it

No confirmed exploitation is on record for CVE-2026-43617. EPSS is 0.32%. Act only if a listed version of Rsync version 3.4.2 and is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Rsync version 3.4.2 and).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.32%
Remediation
Advisory link
Affected products
cpe 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe samba/rsyncversion unspecified

How to fix CVE-2026-43617

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-43617. EPSS is 0.32%. Act only if a listed version of Rsync version 3.4.2 and is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-289. EPSS 0.32%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 20, 2026 · NIST NVD

    Detected

    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

  2. Jul 24, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-43617

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-43617

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-43617

    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,

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.