What’s Vulnerable › Vulnerabilities

CVE-2026-70464: rsync 2.0.0 < 3.5.0 Connection Slot Exhaustion DoS via Handshake Stall

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-13 · updated 2026-10-24
• Weakness: CWE-770

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.

Affected products

• RsyncProject rsync: from 2.0.0 through 3.4.4

References

• https://github.com/RsyncProject/rsync/releases/tag/v3.5.0
• https://github.com/RsyncProject/rsync/security/advisories/GHSA-hrwq-ccf7-rw5m
• https://www.vulncheck.com/advisories/rsync-connection-slot-exhaustion-dos-via-handshake-stall

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