dbcve.org
Secure Email GatewayApplication · Seppmail

CVE-2026-29136

MEDIUM · 6.1 CVSS v3.1 Published 2026-04-02
Fix available
A fix is available. Upgrade to 15.0.3 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 · unedited
SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to inject HTML into notification emails about new CA certificates.

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 · moderate confidence

SEPPmail Secure Email Gateway before version 15.0.3 fails to properly sanitize or encode input in notification emails about new CA certificates, allowing an attacker to inject arbitrary HTML content. This HTML injection in email notifications could enable phishing attacks or credential theft when users view the malicious notifications.

MitigationUpgrade SEPPmail Secure Email Gateway to version 15.0.3 or later to obtain the patched code that properly sanitizes HTML in CA certificate notification emails.

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
Secure Email GatewayApplication
Affected:< 15.0.3

CVSS 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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed SEPPmail version
    Locate the SEPPmail installation and check the version number of the Secure Email Gateway software. This is typically found in the product's about page, system information, or by querying the installed package. Compare your version against the vulnerable range (< 15.0.3).
    Affected if The installed version is lower than 15.0.3 (e.g., 15.0.2, 15.0.1, 14.x, etc.)
  2. Verify CA certificate notification feature is active
    Check the SEPPmail configuration to determine whether the CA certificate notification feature is enabled. Look for settings related to certificate authority (CA) monitoring, certificate alerts, or new certificate notifications in the administrative console or configuration files.
    Affected if The CA certificate notification feature is enabled and configured to send email alerts about new certificates
  3. Review notification email templates
    Examine the email templates or notification configuration used for CA certificate alerts. Look for areas where certificate information (such as issuer name, subject, validity dates) is inserted into notification emails without proper encoding or sanitization.
    Affected if The notification templates accept raw certificate data and inject it into HTML email content without sanitization
  4. Check recent CA certificate notification emails
    Review email logs or quarantine for recent notification emails sent to users regarding CA certificates. Inspect the email source to see if certificate fields appear to be rendered as unencoded HTML content.
    Affected if Recent CA certificate notification emails contain unsanitized HTML or script content in certificate-related fields

A user is affected if their SEPPmail Secure Email Gateway installation is version 14.x or any version below 15.0.3 AND the CA certificate notification feature is enabled, allowing HTML injection in those notification emails.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 15.0.3 or later
Fixed in 15.0.3
Interim mitigation

Upgrade SEPPmail Secure Email Gateway to version 15.0.3 or later to obtain the patched code that properly sanitizes HTML in CA certificate notification emails.

Recommended fix Moderate confidence

15.0.3

  1. Download the SEPPmail Secure Email Gateway version 15.0.3 update from the official vendor source at downloads.seppmail.com
  2. Review the SEPPmail upgrade documentation for the 15.0.3 release
  3. Apply the upgrade following the vendor's recommended upgrade procedure for the Secure Email Gateway appliance
  4. After upgrading, verify that the system is running version 15.0.3
  5. Test that notification emails about new CA certificates are properly sanitized and no longer accept HTML injection

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Secure Email Gateway Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-29136 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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