Skip to content
Fencer Intel
critical 9.1

CVE-2026-53791 json

rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header

published 2mo ago modified 18d ago also EUVD-2026-58099 , GHSA-h2q9-5fr8-w635

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository RsyncProject/rsync. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

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

Is CVE-2026-53791 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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
2mo ago

Exploit prediction

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

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 Intel 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.

The maintainers of RsyncProject/rsync published their own advisory on GitHub. Reviewed sources take precedence over it.