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TI-2026-49228 Aliases CVE-2026-70455

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

Priority MEDIUM 44CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-770.

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00566 47th percentileScored 2026-11-07
Fix Fixed rsync (RsyncProject): 3.5.0Red Hat: 2 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Sambarsync3.4.2 – 3.4.43.5.0Patch availableCNA
  • rsync VendorSamba Affected 3.4.2 – 3.4.4 Fixed in 3.5.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*3.4.2 to before 3.5.0VulnerableSamba
  • cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:* Versions 3.4.2 to before 3.5.0 Vulnerable ·Samba

Remediation

  • Fix · CNA rsync (RsyncProject) Fixed in 3.5.0

Red Hat 2 advisories

  • RHSA-2026:79357 Released 2026-10-08 · Red Hat rating Important
    Red Hat Cost Management On-Premise container image update
    • Red Hat Cost Management On-Premise 1 registry.redhat.io/costmanagement/costmanagement-ui-rhel10
  • RHSA-2026:67463 Released 2026-09-14 · Red Hat rating Important
    rsync security, bug fix, and enhancement update
    • 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

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Cost Management On-Premise 1Fixed RHSA-2026:79357
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:67463
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:67463
Not affected: 6 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-70455
  2. 2026-10-09 Fix available: RHSA-2026:79357 · Red Hat
  3. 2026-10-09 Fix available: Red Hat Cost Management On-Premise 1 · Red Hat
  4. 2026-11-05 Affected versions changed · Red Hat

References

Advisory 1

Other 1

  • TI-2024-11208 Rsync: heap buffer overflow in rsync due to improper checksum length handling CVSS 3.1CRITICAL 9.8
  • TI-2024-11209 Rsync: info leak via uninitialized stack contents CVSS 3.1HIGH 7.5
  • TI-2024-11212 Rsync: --safe-links option bypass leads to path traversal CVSS 3.1HIGH 7.5
  • TI-2024-11211 Rsync: path traversal vulnerability in rsync CVSS 3.1HIGH 7.5
  • TI-2024-11210 Rsync: rsync server leaks arbitrary client files CVSS 3.1MEDIUM 6.8
  • TI-2017-12160 The receive_xattr function in xattrs.c in rsync 3.1.2 and 3.1.3-development does not… CVSS 3.1CRITICAL 9.8
See all 56 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences