What is CVE-2026-35390?

CVE-2026-35390 is a medium-severity vulnerability in Bulwarkmail Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-06.

How severe is CVE-2026-35390?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Bulwarkmail Webmail

CVE-2026-35390

Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.4.11, the reverse proxy (proxy.ts) set the Content-Security-Policy-Report-Only header instead of the enforcing Content-Security-Policy header. This means…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (6.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Bulwarkmail Webmail — versions < 1.4.11

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

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

Frequently asked questions

What is CVE-2026-35390?: CVE-2026-35390 is a medium-severity vulnerability in Bulwarkmail Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-06.
How severe is CVE-2026-35390?: Medium severity. CVSS v3 base score is 5.4 out of 10.