An integer overflow in rsync versions up to 3.4.2 allows a remote sender to cause the receiver to read memory outside the intended buffer, revealing process memory such as environment variables, passwords, and library pointers. This leakage undermines ASLR and can facilitate further attacks by exposing secrets and execution addresses.

RsyncProject rsync versions 3.4.2 and earlier are vulnerable. Organizations using these versions should verify their deployed revision.

The CVSS score of 6.1 indicates moderate severity. The EPSS score is not available and the vulnerability is not listed in CISA’s KEV catalog. The likely attack vector is over an open rsync connection, where an attacker crafts a malicious packet to trigger the overflow. Successful exploitation requires network reachability to the rsync service and the ability to send a crafted sync transfer.