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Fencer Vulns
medium 6.5

CVE-2026-43620 json

Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()

published 2026-05-20 5 mo ago modified 2026-11-08 24 h ago also EUVD-2026-31012 , GHSA-jmf6-74r8-6c28 , JLSEC-2026-631

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in recv_files() in receiver.c that allows a malicious rsync server to crash the rsync client process. Attackers can exploit the vulnerability by setting CF_INC_RECURSE in compatibility flags and sending a specially crafted file list where the first sorted entry is not the leading dot directory, followed by a transfer record with ndx=0 and an iflag word without ITEM_TRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference an invalid pointer at an unmapped address, resulting in a deterministic SIGSEGV crash of the rsync client.

Patch / fix

  • julia rsync_jll 3.4.4+0
  • RsyncProject rsync 3.4.3
  • rsync Debian 12 3.2.7-1+deb12u5
  • rsync Debian 13 3.4.1+ds1-5+deb13u3
  • rsync Debian 14 3.4.3+ds1-1

debian advisories DEBIAN-CVE-2026-43620

  • rsync Ubuntu 22.04 LTS 3.2.7-0ubuntu0.22.04.6
  • rsync Ubuntu 24.04 LTS 3.2.7-1ubuntu1.4
  • rsync Ubuntu 25.10 3.4.1+ds1-5ubuntu1.2
  • rsync Ubuntu 26.04 LTS 3.4.1+ds1-7ubuntu0.2
  • rsync Ubuntu Pro 14.04 LTS 3.1.0-2ubuntu0.4+esm3
  • rsync Ubuntu Pro 16.04 LTS 3.1.1-3ubuntu1.3+esm5
  • rsync Ubuntu Pro 18.04 LTS 3.1.2-2.1ubuntu1.6+esm3
  • rsync Ubuntu Pro 20.04 LTS 3.1.3-8ubuntu0.9+esm1

ubuntu advisories UBUNTU-CVE-2026-43620

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • 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 SLES for SAP applications 16.0, SLES 16.0 3.4.1-160000.4.1

suse advisories SUSE-SU-2026:23289-1SUSE-SU-2026:23323-1SUSE-SU-2026:23253-1SUSE-SU-2026:22015-1

  • rsync openSUSE Leap 16.0 3.4.1-160000.6.1
  • rsync openSUSE Tumbleweed 3.4.3-1.1

opensuse advisories openSUSE-SU-2026:21650-1openSUSE-SU-2026:10857-1

  • rsync Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 3.4.3-r0

alpine advisories ALPINE-CVE-2026-43620

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 3.4.3-1

azure linux advisories AZL-86991

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-2026-43620 updated cvss 6.5

rsync: rsync: Remote Denial of Service via Out-of-bounds Read

  • Red Hat Enterprise Linux 6 rsync Red Hat Enterprise Linux 7 rsync Red Hat Enterprise Linux 8 rsync, rsync-daemon Red Hat Enterprise Linux 9 rsync, rsync-daemon, rsync-rrsync
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 10 rsync
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel9
    under investigation

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
5 mo ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/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
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
OSV 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia rsync_jll
<3.4.4+0
3.4.4+0

Affected products

  • RsyncProject rsync

Classification

Weakness

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.