Vulnerabilities > CVE-2021-23351

047910
CVSS 4.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
HIGH
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
go-proxyproto-project
fedoraproject

Summary

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.