dbcve.org
Secure Email GatewayApplication · Seppmail

CVE-2026-29135

HIGH · 7.5 CVSS v3.1 Published 2026-04-02
Fix available
A fix is available. Upgrade to 15.0.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 craft a password-tag that bypasses subject sanitization.

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 contains a sanitization bypass vulnerability where an attacker can craft a specially designed password-tag to circumvent subject line sanitization. This could allow injection of malicious content into email subjects.

MitigationUpgrade SEPPmail Secure Email Gateway to version 15.0.3 or later to address the password-tag sanitization bypass.

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
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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. Identify installed SEPPmail Secure Email Gateway version
    Access the administration interface or check system information to determine the currently running version of SEPPmail Secure Email Gateway
    Affected if The installed version is any version before 15.0.3 (for example, 15.0.2, 15.0.1, 14.x, etc.)
  2. Verify email subject processing is active
    Confirm that the SEPPmail gateway is configured to process incoming or outgoing email and perform subject line sanitization
    Affected if Email processing with subject sanitization is enabled and the software version is below 15.0.3
  3. Review email gateway configuration for password-tag handling
    Inspect the email gateway configuration settings related to subject line processing and sanitization, specifically any settings involving password-tags or content filtering
    Affected if Password-tag processing in subject lines is enabled and the version is vulnerable
  4. Examine logs for suspicious subject line patterns
    Review SEPPmail gateway logs for any email subjects containing unusual password-tag syntax or patterns that may indicate exploitation attempts
    Affected if Logs show email subjects with password-tags that bypassed sanitization or unexpected content injection

The environment is affected if SEPPmail Secure Email Gateway version is below 15.0.3 and the email subject sanitization feature is actively processing 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 address the password-tag sanitization bypass.

Recommended fix Moderate confidence

15.0.3

  1. 1. Identify the current installed version of SEPPmail Secure Email Gateway using the administrative console or command-line interface
  2. 2. Navigate to the vendor download portal at downloads.seppmail.com
  3. 3. Download SEPPmail Secure Email Gateway version 15.0.3 or later
  4. 4. Review vendor upgrade documentation and release notes for any specific upgrade prerequisites
  5. 5. Apply the upgrade following the vendor's recommended upgrade procedure
  6. 6. Verify the installation was successful and confirm the version is 15.0.3 or later
  7. 7. Test that password-tag handling in email subjects is properly sanitized

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

Fix this in Secure Email Gateway Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.

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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-2026-29135 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