dbcve.org
Secure Email GatewayApplication · Seppmail

CVE-2026-29141

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-02
Fix available
A fix is available. Upgrade to 15.0.3 or later.
See remediation →
62/100
Remediation priority · Elevated
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 bypass subject sanitization and forge tags such as [signed OK].

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 vulnerability allowing attackers to bypass subject sanitization mechanisms. This enables forging security-related tags such as [signed OK] in email subjects, potentially tricking users into believing emails are verified when they are not.

MitigationUpgrade SEPPmail Secure Email Gateway to version 15.0.3 or later to obtain the patch for this vulnerability. Verify subject sanitization is functioning correctly after the update.

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
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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. Identify installed SEPPmail version
    Access the SEPPmail admin interface or check the system version file (typically via command line: 'seppmail --version' or review system information in the admin dashboard under 'System > Status' or 'Help > About')
    Affected if The installed version is any release before 15.0.3 (e.g., 15.0.2, 15.0.1, 14.x, etc.)
  2. Confirm subject sanitization is active
    Navigate to the SEPPmail admin console and locate the email security settings (look for 'Subject Sanitization', 'Security Tags', or 'Email Verification' configuration sections under 'Policy' or 'Security' settings)
    Affected if Subject sanitization is enabled and the gateway version is below 15.0.3, making the bypass possible
  3. Test security tag injection in outbound email subjects
    Send a test email through the gateway with a manually crafted subject line containing '[signed OK]', '[encrypted]', or similar security tags not generated by the system, then verify if these tags appear unmodified in the received email
    Affected if The forged security tags pass through unchanged, confirming the sanitization bypass is present
  4. Review email headers for verification
    Inspect the raw email headers of messages processed by the gateway (via 'View Source' or email client header inspection) to check how security-related tags are handled and whether the gateway validates their origin
    Affected if Security tags in subjects are not being validated or stripped when originating from untrusted sources

You are affected if the installed SEPPmail Secure Email Gateway version is below 15.0.3 and subject sanitization with security tag verification is in use.

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 patch for this vulnerability. Verify subject sanitization is functioning correctly after the update.

Recommended fix Moderate confidence

SEPPmail Secure Email Gateway version 15.0.3

  1. Obtain version 15.0.3 of SEPPmail Secure Email Gateway from the vendor's official download site (downloads.seppmail.com)
  2. Review the upgrade documentation provided with version 15.0.3
  3. Execute the upgrade process according to vendor instructions
  4. After upgrading, verify that subject sanitization is working correctly and cannot be bypassed
  5. Confirm that forged tags such as [signed OK] are no longer injectable into subject lines

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
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.

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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-2026-29141 in production — separate from our analysis above.

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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