CVE-2026-70464: CWE-770 Allocation of Resources Without Limits or Throttling in RsyncProject rsync
rsync daemon 2.0.0 before 3.5.0 contains a denial of service vulnerability that allows unauthenticated remote attackers to exhaust daemon connection slots by stalling the handshake process before or after module selection without triggering the I/O timeout. Attackers can open many simultaneous connections and trickle data at the minimum rate to avoid timeout, or stall entirely before module selection where no timeout applies, consuming all available connection slots and denying service to legitimate clients.
AI Analysis
Technical Summary
CVE-2026-70464 is a denial of service vulnerability in rsync daemon versions 2.0.0 up to and including 3.4.4. The flaw arises because the daemon does not enforce limits or throttling on resource allocation during the handshake process. Attackers can open multiple simultaneous connections and stall the handshake either before or after module selection, avoiding I/O timeouts by trickling data slowly or stalling completely where no timeout applies. This behavior exhausts all available connection slots, preventing legitimate clients from connecting.
Potential Impact
Successful exploitation results in denial of service by consuming all available connection slots on the rsync daemon, thereby preventing legitimate clients from establishing connections. This can disrupt synchronization services relying on rsync, impacting availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider limiting the number of simultaneous connections allowed from a single source or implementing network-level rate limiting to mitigate the impact of connection slot exhaustion.
CVE-2026-70464: CWE-770 Allocation of Resources Without Limits or Throttling in RsyncProject rsync
Description
rsync daemon 2.0.0 before 3.5.0 contains a denial of service vulnerability that allows unauthenticated remote attackers to exhaust daemon connection slots by stalling the handshake process before or after module selection without triggering the I/O timeout. Attackers can open many simultaneous connections and trickle data at the minimum rate to avoid timeout, or stall entirely before module selection where no timeout applies, consuming all available connection slots and denying service to legitimate clients.
CVSS v4.0
Score 8.7high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-70464 is a denial of service vulnerability in rsync daemon versions 2.0.0 up to and including 3.4.4. The flaw arises because the daemon does not enforce limits or throttling on resource allocation during the handshake process. Attackers can open multiple simultaneous connections and stall the handshake either before or after module selection, avoiding I/O timeouts by trickling data slowly or stalling completely where no timeout applies. This behavior exhausts all available connection slots, preventing legitimate clients from connecting.
Potential Impact
Successful exploitation results in denial of service by consuming all available connection slots on the rsync daemon, thereby preventing legitimate clients from establishing connections. This can disrupt synchronization services relying on rsync, impacting availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider limiting the number of simultaneous connections allowed from a single source or implementing network-level rate limiting to mitigate the impact of connection slot exhaustion.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-04T14:52:23.815Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7ddecdbf8831d5395d014b
Added to database: 08/13/2026, 15:12:13 UTC
Last enriched: 08/13/2026, 15:26:28 UTC
Last updated: 08/13/2026, 23:21:53 UTC
Views: 5
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