rsync before 3.5.2 contains a denial of service vulnerability in the delta-transfer sender's hash_search() in match.c that allows malicious receivers to trigger unbounded strong-checksum work at consecutive offsets. Unauthenticated attackers pulling from a public daemon module can supply weak checksums colliding with consecutive rolling windows plus non-matching strong checksums, exhausting sender CPU across concurrent connections.

rsync through 3.5.1 contains a denial of service vulnerability in the delta-transfer sender's hash_search() in match.c that allows malicious receivers to trigger unbounded strong-checksum work at consecutive offsets. Unauthenticated attackers pulling from a public daemon module can supply weak checksums colliding with consecutive rolling windows plus non-matching strong checksums, exhausting sender CPU across concurrent connections.