CVE-2026-35391: CWE-348: Use of Less Trusted Source in bulwarkmail webmail
CVE-2026-35391 is a high-severity vulnerability in Bulwark Webmail versions prior to 1. 4. 11. The vulnerability arises because the getClientIP() function trusts the first entry of the X-Forwarded-For header, which can be manipulated by an attacker. This allows attackers to forge their source IP address, potentially bypassing IP-based rate limiting and enabling brute-force attacks against the admin login. Additionally, attackers can forge audit log entries to mask malicious activity. The issue is fixed in version 1. 4. 11.
AI Analysis
Technical Summary
Bulwark Webmail, a self-hosted webmail client for Stalwart Mail Server, has a vulnerability (CVE-2026-35391) in versions before 1.4.11 where the getClientIP() function in lib/admin/session.ts incorrectly trusts the first (leftmost) IP address in the X-Forwarded-For HTTP header. Since this header is fully client-controlled, an attacker can supply a forged IP address. This can be exploited to bypass IP-based rate limiting mechanisms, facilitating brute-force attacks on the admin login, and to forge audit logs, making malicious actions appear to originate from arbitrary IPs. The vulnerability is classified under CWE-348 (Use of Less Trusted Source) and has a CVSS 4.0 score of 8.7 (high severity). The vulnerability is fixed in Bulwark Webmail version 1.4.11.
Potential Impact
An attacker can bypass IP-based rate limiting protections by forging the X-Forwarded-For header, enabling brute-force attacks against the admin login. Additionally, audit logs can be manipulated to hide the true source of malicious activity by forging IP addresses. This undermines both access control and forensic capabilities of the affected system.
Mitigation Recommendations
Upgrade Bulwark Webmail to version 1.4.11 or later, where this vulnerability is fixed. Since the vendor advisory confirms the issue is resolved in 1.4.11, applying this official fix is the recommended remediation. No other mitigation steps are indicated.
CVE-2026-35391: CWE-348: Use of Less Trusted Source in bulwarkmail webmail
Description
CVE-2026-35391 is a high-severity vulnerability in Bulwark Webmail versions prior to 1. 4. 11. The vulnerability arises because the getClientIP() function trusts the first entry of the X-Forwarded-For header, which can be manipulated by an attacker. This allows attackers to forge their source IP address, potentially bypassing IP-based rate limiting and enabling brute-force attacks against the admin login. Additionally, attackers can forge audit log entries to mask malicious activity. The issue is fixed in version 1. 4. 11.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Bulwark Webmail, a self-hosted webmail client for Stalwart Mail Server, has a vulnerability (CVE-2026-35391) in versions before 1.4.11 where the getClientIP() function in lib/admin/session.ts incorrectly trusts the first (leftmost) IP address in the X-Forwarded-For HTTP header. Since this header is fully client-controlled, an attacker can supply a forged IP address. This can be exploited to bypass IP-based rate limiting mechanisms, facilitating brute-force attacks on the admin login, and to forge audit logs, making malicious actions appear to originate from arbitrary IPs. The vulnerability is classified under CWE-348 (Use of Less Trusted Source) and has a CVSS 4.0 score of 8.7 (high severity). The vulnerability is fixed in Bulwark Webmail version 1.4.11.
Potential Impact
An attacker can bypass IP-based rate limiting protections by forging the X-Forwarded-For header, enabling brute-force attacks against the admin login. Additionally, audit logs can be manipulated to hide the true source of malicious activity by forging IP addresses. This undermines both access control and forensic capabilities of the affected system.
Mitigation Recommendations
Upgrade Bulwark Webmail to version 1.4.11 or later, where this vulnerability is fixed. Since the vendor advisory confirms the issue is resolved in 1.4.11, applying this official fix is the recommended remediation. No other mitigation steps are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-02T17:03:42.074Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d417e60a160ebd92da7f8b
Added to database: 4/6/2026, 8:30:30 PM
Last enriched: 4/14/2026, 4:00:29 PM
Last updated: 5/22/2026, 5:29:25 PM
Views: 81
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