dbcve.org
Secure Email GatewayApplication · Seppmail

CVE-2026-29131

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 attackers with a specially crafted email address to read the contents of emails encrypted for other users.

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 confidence

SEPPmail Secure Email Gateway before version 15.0.3 contains a vulnerability where attackers using a specially crafted email address can read the contents of emails encrypted for other users, indicating a cross-user confidentiality breach likely stemming from improper email address handling or validation in the encryption gateway.

MitigationUpgrade SEPPmail Secure Email Gateway to version 15.0.3 or later to remediate this vulnerability.

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. Verify SEPPmail installation exists
    Check for SEPPmail Secure Email Gateway installation by looking for its software components, service processes, or installation directory on the system.
    Affected if SEPPmail Secure Email Gateway is not installed on the system.
  2. Determine installed version
    Locate and read the SEPPmail version information, typically found in the product's admin interface, version file, or system information panel. Common locations include /opt/seppmail, the web admin console, or system package management.
    Affected if The installed version cannot be determined or the product is not present.
  3. Compare version to vulnerability threshold
    Compare the identified version number against the vulnerable range. The product is affected if the version is lower than 15.0.3 (for example: 15.0.2, 15.0.1, 14.x, or earlier versions).
    Affected if The installed version is below 15.0.3, indicating the system falls within the vulnerable version range.
  4. Confirm encryption gateway is active
    Verify that the email encryption/decryption gateway functionality is enabled. Check the SEPPmail configuration for encryption module status, typically accessible through the admin interface under encryption settings or gateway configuration.
    Affected if The encryption gateway is not enabled or not in use, the vulnerability may not be exploitable in the current deployment.
  5. Inspect email address handling configuration
    Review the email routing and encryption configuration for how recipient email addresses are processed and validated during encryption operations. Look for settings related to address normalization or key lookup.
    Affected if The system processes incoming encrypted emails and routes them to users, with address handling configuration present.

The environment is affected if SEPPmail Secure Email Gateway version below 15.0.3 is installed and the email encryption gateway feature is enabled, allowing processing of encrypted 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 remediate this vulnerability.

Recommended fix High confidence

15.0.3 or later

  1. Obtain SEPPmail Secure Email Gateway version 15.0.3 from the official vendor download site at downloads.seppmail.com
  2. Follow SEPPmail's standard upgrade procedure for the Secure Email Gateway product
  3. After upgrade, verify the version is 15.0.3 or later by checking the product console or About page

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

Fix this in Secure Email Gateway Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-29131 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-29131 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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