CVE-2026-35390CWE-79

Content-Security-Policy was set to Report-Only mode, failing to block XSS attacks

Medium · published April 6, 2026

CVSS v4.0
5.3
EPSS
0%
Percentile
13.4
In the wild
Unconfirmed
What it is

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 cross-site scripting (XSS) attacks were logged but not blocked. Any user who could inject script content (e.g., via crafted email HTML) could execute arbitrary JavaScript in the context of the application, potentially stealing session tokens or performing actions on behalf of the user. This vulnerability is fixed in 1.4.11.

The record
Technical detail
CVSS v4.0
5.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
EPSS
0.00233 · 13.4th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-04-06T20:13Z
EPSS history
Timeline
  • 06 APR 20:13Z
    Content-Security-Policy was set to Report-Only mode, failing to block XSS attacks
    cvelistv5