bulwarkmail webmail up to 1.4.10 Email Content-Security-Policy-Report-Only cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, has been found in bulwarkmail webmail up to 1.4.10. This affects an unknown function of the component Email Handler. Performing a manipulation of the argument Content-Security-Policy-Report-Only results in cross site scripting. This vulnerability is identified as CVE-2026-35390. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in bulwarkmail webmail up to 1.4.10. This affects an unknown functionality of the component Email Handler. The manipulation of the argument Content-Security-Policy-Report-Only with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. The summary by CVE 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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-35390 since 04/02/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 1.4.11 eliminates this vulnerability.

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Productinfo

Type

• Mail Client Software

Vendor

• bulwarkmail

Name

• webmail

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10

Website

• Product: https://github.com/bulwarkmail/webmail/

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