CVE-2026-29143 | SEPPmail Secure Email Gateway up to 15.0.2 SMIME Message improper authentication

VDB-354844 · CVE-2026-29143 · GCVE-0-2026-29143 SEPPMAIL SECURE EMAIL GATEWAY UP TO 15.0.2 SMIME MESSAGE IMPROPER AUTHENTICATION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.0 $0-$5k 1.52+ Summaryinfo A vulnerability classified as critical was found in SEPPmail Secure Email Gateway up to 15.0.2. The affected element is an unknown function of the component SMIME Message Handler. Executing a manipulation can lead to improper authentication. The identification of this vulnerability is CVE-2026-29143. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised. Detailsinfo A vulnerability classified as critical was found in SEPPmail Secure Email Gateway up to 15.0.2. This vulnerability affects an unknown function of the component SMIME Message Handler. The manipulation with an unknown input leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes: SEPPmail Secure Email Gateway before version 15.0.3 does not properly authenticate the inner message of S/MIME-encrypted MIME entities, allowing an attacker to control trusted headers. The weakness was shared by Andris Suter-Dörig. The advisory is shared for download at downloads.seppmail.com. This vulnerability was named CVE-2026-29143 since 03/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. Upgrading to version 15.0.3 eliminates this vulnerability. Productinfo Vendor SEPPmail Name Secure Email Gateway Version 15.0.0 15.0.1 15.0.2 CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA CVSS-B Score: 🔒 CNA CVSS-BT Score: 🔒 CNA Vector: 🔒 CVSSv3info VulDB Meta Base Score: 7.3 VulDB Meta Temp Score: 7.0 VulDB Base Score: 7.3 VulDB Temp Score: 7.0 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Improper authentication CWE: CWE-287 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Secure Email Gateway 15.0.3 Timelineinfo 03/04/2026 CVE reserved 04/02/2026 +28 days Advisory disclosed 04/02/2026 +0 days VulDB entry created 04/02/2026 +0 days VulDB entry last update Sourcesinfo Advisory: downloads.seppmail.com Researcher: Andris Suter-Dörig Status: Confirmed CVE: CVE-2026-29143 (🔒) GCVE (CVE): GCVE-0-2026-29143 GCVE (VulDB): GCVE-100-354844 Entryinfo Created: 04/02/2026 11:22 Changes: 04/02/2026 11:22 (68) Complete: 🔍 Cache ID: 99:A0D:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸