IP Spoofing Vulnerability in Bulwark Webmail by Stalwart Mail Server
CVE-2026-35391

8.7HIGH

Key Information:

Vendor

Bulwarkmail

Status
Webmail
Vendor
CVE Published:
6 April 2026

What is CVE-2026-35391?

Bulwark Webmail, a self-hosted client for the Stalwart Mail Server, is vulnerable due to the improper validation of the X-Forwarded-For header in the getClientIP() function of lib/admin/session.ts. This oversight allows attackers to manipulate their source IP address, facilitating brute-force attacks against the admin login by bypassing IP rate limiting measures. Additionally, malicious actors can forge audit log entries, misleadingly attributing unauthorized activities to legitimate IP addresses. This vulnerability is resolved in version 1.4.11.

Affected Version(s)

webmail < 1.4.11

References

https://github.com/bulwarkmail/webmail/security/advisorie...
x_refsource_CONFIRM

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.