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Fencer Vulns
critical 9.1

CVE-2026-53791 json

rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header

published 2026-08-13 2 mo ago modified 2026-10-24 15 d ago also EUVD-2026-58099

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

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.

Patch / fix

  • RsyncProject rsync 3.5.0
  • rsync Debian 12 3.5.0+ds1-0+deb12u1
  • rsync Debian 13 3.5.0+ds1-0+deb13u1
  • rsync Debian 14 3.5.0+ds1-1

debian advisories DEBIAN-CVE-2026-53791

  • rsync RHEL 10.2 3.5.0-3.el10_2
  • rsync-daemon RHEL 10.2 3.5.0-3.el10_2
  • rsync-rrsync RHEL 10.2 3.5.0-3.el10_2
  • rsync RHEL 9 3.2.7-1.el9_8
  • rsync-daemon RHEL 9 3.2.7-1.el9_8
  • rsync-rrsync RHEL 9 3.2.7-1.el9_8

red hat advisories RHSA-2026:67463RHSA-2026:67462

  • rsync SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.4.1-160000.6.1
  • rsync Linux Micro 6.0 3.2.7-8.1
  • rsync Linux Micro 6.1 3.3.0-slfo.1.1_7.1
  • rsync SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 3.2.7-150600.3.24.1
  • rsync SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 3.2.3-150400.3.34.1

suse advisories SUSE-SU-2026:23289-1SUSE-SU-2026:23323-1SUSE-SU-2026:23253-1SUSE-SU-2026:23254-1SUSE-SU-2026:3657-1SUSE-SU-2026:3634-1

  • rsync openSUSE Tumbleweed 3.5.1-1.1
  • rsync openSUSE Leap 16.0 3.4.1-160000.6.1

opensuse advisories openSUSE-SU-2026:11869-1openSUSE-SU-2026:21650-1

  • rsync AlmaLinux 9 3.2.7-1.el9_8
  • rsync-daemon AlmaLinux 9 3.2.7-1.el9_8
  • rsync-rrsync AlmaLinux 9 3.2.7-1.el9_8
  • rsync AlmaLinux 10 3.5.0-3.el10_2
  • rsync-daemon AlmaLinux 10 3.5.0-3.el10_2
  • rsync-rrsync AlmaLinux 10 3.5.0-3.el10_2

almalinux advisories ALSA-2026:67462ALSA-2026:67463

  • rsync Rocky Linux 9 3.2.7-1.el9_8
  • rsync Rocky Linux 10 3.5.0-3.el10_2

rocky linux advisories RLSA-2026:67462RLSA-2026:67463

  • rsync Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 3.5.0-r0

alpine advisories ALPINE-CVE-2026-53791

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rsync Azure Linux 3.0 3.5.0-1

azure linux advisories AZL-95783

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-53791 updated cvss 7.4

rsync: rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header

  • Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).”
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1791460851
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:79357
  • Red Hat Enterprise Linux AppStream (v. 9) rsync-daemon 3.2.7-1.el9_8, rsync-rrsync 3.2.7-1.el9_8
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:67462
  • Red Hat Enterprise Linux AppStream (v. 10) rsync-daemon 3.5.0-3.el10_2, rsync-rrsync 3.5.0-3.el10_2
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:67463
  • Red Hat Enterprise Linux BaseOS (v. 9) rsync 3.2.7-1.el9_8
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:67462
  • Red Hat Enterprise Linux BaseOS (v. 10) rsync 3.5.0-3.el10_2
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:67463
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202609221802
    fixed: vendor fix “Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).” RHSA-2026:71446
  • Red Hat Enterprise Linux 6 rsync Red Hat Enterprise Linux 7 rsync Red Hat Enterprise Linux 8 rsync, rsync-daemon Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 9.1 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
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA 4.0 9.1 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:X/V:X/RE:X/U:X

Affected products

  • RsyncProject rsync

Classification

Weakness
  • CWE-290 Authentication Bypass by Spoofing

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.