S/MIME Signature Additional Certificate

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-29140
StatePUBLISHED
AssignerNCSC.ch
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-02 09:16:22 UTC
Updated2026-04-02 09:16:22 UTC
DescriptionSEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to cause attacker-controlled certificates to be used for future encryption to a victim by adding the certificates to S/MIME signatures.

Risk And Classification

Primary CVSS: v4.0 7.7 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-295 | CWE-295 CWE-295 Improper Certificate Validation

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/C...
4.0CNACVSS7.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Sub Conf.
High
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA SEPPmail Secure Email Gateway affected 15.0.3 custom Not specified

References

ReferenceSourceLinkTags
downloads.seppmail.com/extrelnotes/150/ERN15.0.html [email protected] downloads.seppmail.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Andris Suter-Dörig (en)

CNA: Matteo Scarlata (en)

CNA: Kenny Paterson (en)

Additional Advisory Data

SourceTimeEvent
CNA2025-10-31T14:22:00.000ZVulnerability disclosed to SEPPmail
CNA2026-03-03T00:00:00.000ZVersion 15.0.3 released
© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

CVE.report and Source URL Uptime Status status.cve.report