Puma web server versions 5.5.0 through 7.2.0 and 8.0.0 through 8.0.1 are vulnerable to source IP spoofing when PROXY protocol v1 is enabled and persistent connections are used. The vulnerability arises because Puma incorrectly re-parses PROXY protocol headers on persistent connections, allowing an attacker to inject repeated PROXY headers and overwrite the REMOTE_ADDR value. This can mislead applications relying on REMOTE_ADDR for security decisions. The issue is fixed in Puma versions 7.2.1 and 8.0.2.