Vulnerability record · CVE-2026-53791 · published 13 August 2026

CVE-2026-53791: Samba rsync authentication bypass by spoofing vulnerability

Samba · Rsync

rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.

9.1 CVSS 4.0 Critical EPSS 0.71% · top 48.4% CWE-290 · Authentication bypass by spoofing

9.1CVSS 4.0 base score

0.71%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

3References

31 Aug 2026Last modified by NVD

Description

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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.

Rsync Samba

References

Link	Tags
https://github.com/RsyncProject/rsync/releases/tag/v3.5.0	ProductRelease Notes
https://github.com/RsyncProject/rsync/security/advisories/GHSA-h2q9-5fr8-w635	Vendor Advisory
https://www.vulncheck.com/advisories/rsync-daemon-ip-spoofing-via-proxy-protocol-header	Release NotesThird Party Advisory

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Related vulnerabilities

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

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Source: NIST National Vulnerability Database (record CVE-2026-53791), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.