GHSA-fqh4-rh59-xhvf github.com/pires/go-proxyproto denial of service vulnerability

• Go github.com/pires/go-proxyproto: < 0.5.0 → fixed in 0.5.0

The package `github.com/pires/go-proxyproto` before 0.5.0 are vulnerable to Denial of Service (DoS) via the `parseVersion1()` function. The reader in this package is a default `bufio.Reader` wrapping a `net.Conn`. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.