TI-2026-27526 Aliases CVE-2026-35390

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

LOW 23CWE-79Published 2026-04-06 · Updated 2026-04-07

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Cross-site scripting
Confidentiality · integrity · availability: None · None · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00173 6th percentileScored 2026-11-07

Fix Fixed webmail (bulwarkmail): 1.4.11

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
bulwarkmail	webmail	before 1.4.11	1.4.11	Patch available	CNA

webmail Vendorbulwarkmail Affected before 1.4.11 Fixed in 1.4.11 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:bulwarkmail:webmail::::::::	before 1.4.11	Vulnerable	bulwarkmail

cpe:2.3:a:bulwarkmail:webmail:*:*:*:*:*:*:*:* Versions before 1.4.11 Vulnerable ·bulwarkmail

Remediation

Fix · CNA webmail (bulwarkmail) Fixed in 1.4.11

Timeline

2026-10-02 Threatist record created from CVE-2026-35390

References

Advisory 1

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-6q52-98cr-qx65

TI-2026-27078 Bulwark Webmail: Authentication Bypass in verifyIdentity() due to missing cookie validation CVSS 4.0HIGH 8.7
TI-2026-27077 Bulwark Webmail: Information Exposure: password returned in /api/auth/session CVSS 4.0HIGH 8.7
TI-2026-27527 Bulwark Webmail getClientIP() trusted client-controlled X-Forwarded-For value, enabling… CVSS 4.0HIGH 8.7
TI-2026-27525 Bulwark Webmail S/MIME signature verification accepted self-signed certificates CVSS 4.0HIGH 8.7

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences