CVE-2026-2743

critical

Published 2026-03-05 · Modified 2026-05-19

CVSS v3

9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2

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VIR risk

9.8

Description

Arbitrary File Write via Path Traversal upload to Remote Code Execution in SeppMail User Web Interface. The affected feature is the large file transfer (LFT). This issue affects SeppMail: 15.0.2.1 and before

Predictions

Exploit likelihood

97%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: vulnerability@ncsc.ch — https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html

Application impact

Vendor	Product	Versions	Fixed
seppmail	seppmail	`{"endIncluding":"15.0.2.1"}`

References

https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html
https://labs.infoguard.ch/posts/seppmail_secure_e-mail_gateway_rce_vulnerabilities_cve-2026-2743_cve-2026-7864_cve-2026-44127_cve-2026-44128/
https://labs.infoguard.ch/posts/seppmail_secure_e-mail_gateway_rce_vulnerabilities_cve-2026-2743_cve-2026-7864_cve-2026-44127_cve-2026-44128/

CWEs

CWE-22 CWE-434

Verify integrity in audit chain (admin only). AS-IS.