CVE-2026-35389 PUBLISHED

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

Assigner: GitHub_M
Reserved: 02.04.2026 Published: 06.04.2026 Updated: 06.04.2026

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.

Metrics

CVSS 4.0

CVSS Vector: 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
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	bulwarkmail
Product	webmail
Versions	Version < 1.4.11 is affected

References

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

Problem Types

CWE-295: Improper Certificate Validation CWE