CVE-2025-31135 — MEDIUM (5.3)

Vulnerability 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.

CVSS Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

LOW

Availability

NONE

Related Weaknesses (CWE)

CWE-20

References

FAQ

What is CVE-2025-31135?

CVE-2025-31135 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 earli...

How severe is CVE-2025-31135?

CVE-2025-31135 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-31135?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.