What is CVE-2026-35389?

CVE-2026-35389 is a high-severity vulnerability in Bulwarkmail Webmail, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2026-04-06.

How severe is CVE-2026-35389?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Bulwarkmail Webmail

CVE-2026-35389

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 cer…

Vulnerability class: Improper Certificate Validation

EPSS: 0.002 (7.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Bulwarkmail Webmail — versions < 1.4.11

Weakness classification (CWE)

CWE-295 — Improper Certificate Validation

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-35389?: CVE-2026-35389 is a high-severity vulnerability in Bulwarkmail Webmail, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2026-04-06.
How severe is CVE-2026-35389?: High severity. CVSS v3 base score is 7.5 out of 10.