Cross-site scripting via report-only content security policy
Published Apr 6, 2026 · Updated Apr 6, 2026
Cross-site scripting in Bulwark Webmail before 1.4.11 allows remote attackers to execute JavaScript through crafted email HTML. The proxy.ts reverse proxy sends Content-Security-Policy-Report-Only instead of Content-Security-Policy, so browsers report injected scripts without blocking them. Exploitation requires a recipient to render attacker-controlled content and can expose session tokens or perform actions with that user's session.
Summary
What happened
Cross-site scripting in Bulwark Webmail before 1.4.11 allows remote attackers to execute JavaScript through crafted email HTML. The proxy.ts reverse proxy sends Content-Security-Policy-Report-Only instead of Content-Security-Policy, so browsers report injected scripts without blocking them. Exploitation requires a recipient to render attacker-controlled content and can expose session tokens or perform actions with that user's session.
The record
- CVE
- CVE-2026-35390
- Published
- Apr 6, 2026
- Updated
- Apr 6, 2026
- Vendor
- Bulwark Mail
- Product
- Bulwark Webmail
- Classifications
- CWE-79, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 6, 2026CVE publishedPublication date reported by the CVE source.
- Apr 6, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.4.11
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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