CVE-2026-35389
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, S/MIME signature verification did not validate the certificate trust chain (checkChain: false). Any email signed with a self-signed or untrusted certificate was displayed as having a valid signature. 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 S/MIME signature verification had certificate trust chain validation disabled (checkChain: false), causing emails signed with self-signed or untrusted certificates to be incorrectly displayed as having valid signatures. This allows attackers to forge seemingly legitimate signed emails by using arbitrary certificates.
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 Bulwark Webmail versionLocate and read the version information for your Bulwark Webmail installation (typically found in application metadata, about page, or version file)Affected if Version is below 1.4.11
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Verify S/MIME is in useCheck if S/MIME email signing/verification is enabled or used in your Bulwark Webmail configuration or logsAffected if S/MIME functionality is active and version is below 1.4.11
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Inspect S/MIME certificate chain validation settingLocate and examine the S/MIME configuration file or settings related to certificate chain validation (checkChain or equivalent parameter)Affected if checkChain is explicitly disabled or certificate chain validation is disabled
Your environment is affected if Bulwark Webmail version is below 1.4.11 and S/MIME signature verification is actively used, since self-signed or untrusted certificates would incorrectly display as valid.
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 Bulwark Webmail version 1.4.11 or later to enable certificate chain validation. Review existing stored emails to identify any that were incorrectly validated as having valid signatures.
1.4.11
- Back up your current Webmail installation and configuration before upgrading
- Upgrade Bulwark Webmail to version 1.4.11 or later
- After upgrading, verify that S/MIME signature verification now properly validates certificate trust chains
- Test with an email signed with a self-signed certificate to confirm it is now properly flagged as untrusted
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 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-2026-35389 — 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-2026-35389 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data