CVE-2026-70455: CWE-770 Allocation of Resources Without Limits or Throttling in RsyncProject rsync
Rsync versions 3.4.2 through 3.4.4 contain a denial of service vulnerability where a remote sender can exhaust system resources by abusing the --zt alias for --compress-threads. This bypasses option filtering and allows spawning an unbounded number of worker threads, leading to resource exhaustion.
AI Analysis
Technical Summary
CVE-2026-70455 is a denial of service vulnerability in rsync versions 3.4.2 up to and including 3.4.4. The issue arises because the short alias --zt for --compress-threads bypasses the refuse options directive's string matching on long option names. An attacker can specify --zt=N with a large value to cause the receiver to spawn an unbounded number of Zstandard compression worker threads, exhausting thread and memory resources on the target system.
Potential Impact
A remote attacker can cause a denial of service by exhausting system resources such as threads and memory on the rsync receiver, potentially disrupting legitimate synchronization operations and impacting system availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider restricting or monitoring usage of the --zt option in rsync or limiting resource usage by rsync processes where possible.
CVE-2026-70455: CWE-770 Allocation of Resources Without Limits or Throttling in RsyncProject rsync
Description
Rsync versions 3.4.2 through 3.4.4 contain a denial of service vulnerability where a remote sender can exhaust system resources by abusing the --zt alias for --compress-threads. This bypasses option filtering and allows spawning an unbounded number of worker threads, leading to resource exhaustion.
CVSS v4.0
Score 8.7high
Affected software
RsyncProject
rsync
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-70455 is a denial of service vulnerability in rsync versions 3.4.2 up to and including 3.4.4. The issue arises because the short alias --zt for --compress-threads bypasses the refuse options directive's string matching on long option names. An attacker can specify --zt=N with a large value to cause the receiver to spawn an unbounded number of Zstandard compression worker threads, exhausting thread and memory resources on the target system.
Potential Impact
A remote attacker can cause a denial of service by exhausting system resources such as threads and memory on the rsync receiver, potentially disrupting legitimate synchronization operations and impacting system availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider restricting or monitoring usage of the --zt option in rsync or limiting resource usage by rsync processes where possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-04T14:52:23.814Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a7ddecabf8831d5395d005c
Added to database: 08/13/2026, 15:12:10 UTC
Last enriched: 08/21/2026, 13:25:57 UTC
Last updated: 09/28/2026, 19:29:09 UTC
Views: 47
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