CVE-2026-35389

Bulwark Webmail S/MIME signature verification accepted self-signed certificates

State: Published
Severity: 8.7 High
Published: Apr 6, 2026
Updated: Apr 7, 2026
Reserved: Apr 2, 2026

Description

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, S/MIME signature verification did not validate the certificate trust chain (checkChain: false). Any email signed with a self-signed or untrusted certificate was displayed as having a valid signature. This vulnerability is fixed in 1.4.11.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-295 Improper Certificate Validation

Affected Products

Product	Versions
webmailbulwarkmail	< 1.4.11Affected

References

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-v6w6-338p-p256

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