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.

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History

Fri, 14 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 14 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Samba
Samba rsync
CPEs cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*
Vendors & Products Samba
Samba rsync

Fri, 14 Aug 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Rsync Project
Rsync Project rsync
Vendors & Products Rsync Project
Rsync Project rsync

Thu, 13 Aug 2026 15:15:00 +0000

Type Values Removed Values Added
Description 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.
Title rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-14T19:45:47.934Z

Reserved: 2026-08-04T14:52:23.814Z

Link: CVE-2026-70455

cve-icon Vulnrichment

Updated: 2026-08-14T18:30:21.730Z

cve-icon NVD

Status : Received

Published: 2026-08-13T15:19:59.197

Modified: 2026-08-14T20:16:56.100

Link: CVE-2026-70455

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-14T10:00:03Z

Weaknesses