CVE-2025-31135

Medium

Description

Go-Guerrilla SMTP Daemon is a lightweight SMTP server written in Go. Prior to 1.6.7, when ProxyOn is enabled, the PROXY command will be accepted multiple times, with later invocations overriding earlier ones. The proxy protocol only supports one initial PROXY header; anything after that is considered part of the exchange between client and server, so the client is free to send further PROXY commands with whatever data it pleases. go-guerrilla will treat these as coming from the reverse proxy, allowing a client to spoof its IP address. This vulnerability is fixed in 1.6.7.

SeverityMedium
CVSS5.3
Exploit probability—
ProductGithub.com/phires/go-guerrilla
PublishedApr 1, 2025
First seenApr 1, 2025

How to fix

Update
  • github.com/phires/go-guerrilla1.6.7 or later

Affected products

ProductAffected versionsFixed in
github.com/phires/go-guerrillaGov < 1.6.71.6.7

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