Skip to content
Fencer Intel
high 7.5

CVE-2026-70455 json

rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion

published 2mo ago modified 18d ago also EUVD-2026-58049 , GHSA-rjvj-qgqg-cvx9

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
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

rsync 3.4.2 before 3.5.0 contains a denial of service vulnerability that allows a remote sender to exhaust system resources by specifying the --zt short alias for --compress-threads, which bypasses the refuse options directive's string matching on long option names. Attackers can specify --zt=N with a large value to spawn an unbounded number of Zstandard worker threads on the receiver, exhausting available thread and memory resources.

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-2026-70455

  • 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

red hat advisories RHSA-2026:67463

  • 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 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-2026:67463

  • rsync Rocky Linux 10 3.5.0-3.el10_2

rocky linux advisories RLSA-2026:67463

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

alpine advisories ALPINE-CVE-2026-70455

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-95807

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-2026-70455 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-2026-70455 updated cvss 7.5

rsync: rsync: Denial of Service via Zstandard compression thread exhaustion

  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1791460851
    fixed: vendor fix RHSA-2026:79357
  • Red Hat Enterprise Linux AppStream (v. 10) rsync-daemon 3.5.0-3.el10_2, rsync-rrsync 3.5.0-3.el10_2 Red Hat Enterprise Linux BaseOS (v. 10) rsync 3.5.0-3.el10_2
    fixed: vendor fix RHSA-2026:67463
  • 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 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    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
yes
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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

Affected products

  • RsyncProject rsync

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.