CVE-2026-35391
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the getClientIP() function in lib/admin/session.ts trusted the first (leftmost) entry of the X-Forwarded-For header, which is fully controlled by the client. An attacker could forge their source IP address to bypass IP-based rate limiting (enabling brute-force attacks against the admin login) or forge audit log entries (making malicious activity appear to originate from arbitrary IP addresses). This vulnerability is fixed in 1.4.11.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBulwark Webmail's getClientIP() function in lib/admin/session.ts incorrectly trusts the first (leftmost) entry of the X-Forwarded-For HTTP header, which is fully client-controllable. Attackers can spoof their source IP address to bypass IP-based rate limiting (enabling brute-force admin login attacks) and forge audit log entries to obscure malicious activity origins.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.4.11CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Bulwarkmail Webmail versionLook for a version file, check package.json, or run a version command if available (such as 'bulwarkmail --version' or checking the web interface for a version display)Affected if The installed version is below 1.4.11
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Identify if the application uses X-Forwarded-For headersInspect HTTP requests to the application for the presence of X-Forwarded-For headers, or check proxy configuration files (nginx.conf, apache config, etc.) to see if X-Forwarded-For is being setAffected if The application or its reverse proxy processes X-Forwarded-For headers and the first entry can be user-controlled
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Verify IP-based rate limiting is in useCheck application configuration files for rate limiting rules, or examine the lib/admin/session.ts file if accessible to see if getClientIP() is called by rate limiting logicAffected if IP-based rate limiting relies on getClientIP() to identify clients
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Check if the application is deployed behind a reverse proxyReview network architecture documentation or server configuration to determine if a reverse proxy (nginx, Apache, HAProxy, cloud load balancer) sits in front of Bulwarkmail WebmailAffected if A reverse proxy is present and X-Forwarded-For headers from clients are not being overwritten (only appended to)
You are affected if running Bulwarkmail Webmail version below 1.4.11 and your environment processes X-Forwarded-For headers that can be controlled by clients (typically when not behind a properly configured reverse proxy that overwrites the header).
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.4.11
Upgrade to version 1.4.11 or later which implements proper IP validation. As immediate workarounds, ensure the application sits behind a trusted reverse proxy that overwrites X-Forwarded-For, or implement additional authentication controls (e.g., MFA, account lockout policies) to mitigate brute-force risk while the upgrade is being applied.
1.4.11 or later
- Identify the current Bulwark Webmail version in use
- Download or access the updated Bulwark Webmail version 1.4.11 or later from the official GitHub repository
- Upgrade the Bulwark Webmail installation to version 1.4.11 following the project's standard upgrade procedure
- Verify that the getClientIP() function now properly validates the X-Forwarded-For header (e.g., by checking lib/admin/session.ts in the source)
- Test that IP-based rate limiting now correctly uses the trusted proxy IP rather than client-supplied values
- Confirm admin login and audit logging work correctly with the fix
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-35391 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-35391 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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