rsync <3.5.0 DOS via hash_search algorithmic complexity
CVE-2026-70453 Published on August 13, 2026
rsync < 3.5.0 Algorithmic Complexity DoS via hash_search()
rsync before 3.5.0 contains an algorithmic complexity vulnerability in the hash_search() function that allows a remote attacker to cause a denial of service by delivering a carefully constructed file list. A sender can exploit the quadratic-time worst-case behavior in hash lookups to exhaust receiver CPU resources with a modest number of crafted entries, causing a sustained denial of service.
Vulnerability Analysis
CVE-2026-70453 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
Inefficient Algorithmic Complexity
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
Products Associated with CVE-2026-70453
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Affected Versions
RsyncProject rsync:- Before and including 3.4.4 is affected.
- Version 3.5.0 is unaffected.