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Vulnerability IntelligenceCVE-2026-35389

CVE-2026-35389

HIGH8.7

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

Published Apr 6, 2026

Modified 2 weeks ago

Details

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.

References

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

https://www.cve.org/CVERecord?id=CVE-2026-35389

CVSS Analysis

CVSS v4.0

8.7

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Attack Requirements

NoneAT:N

Privileges Required

NonePR:N

User Interaction

NoneUI:N

Vulnerable System

Vuln. Confidentiality

NoneVC:N

Vuln. Integrity

HighVI:H

Vuln. Availability

NoneVA:N

Subsequent System

Subseq. Confidentiality

NoneSC:N

Subseq. Integrity

NoneSI:N

Subseq. Availability

NoneSA:N

8.7/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

Weakness Type (CWE)

Cryptography

Improper Certificate Validation

Ecosystems

Timeline

PublishedApr 6, 2026

ModifiedApr 7, 2026

CVE-2026-35389 | Mondoo Vulnerability Intelligence