CVE-2026-113728
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk43th percentile - higher than 43% of all known CVEs
Summary
In Bulwark Webmail prior to 1.9.2, the unauthenticated POST /api/fetch-ical endpoint validates a caller-supplied hostname with one DNS lookup and then performs a separate lookup for the connection. An attacker controlling authoritative DNS can return a public address during validation and then rebind the hostname to a loopback, private, link-local, or cloud metadata address, causing the server to return up to 10 MB of an internal HTTP or HTTPS response.
Risk Assessment
The SSRF flaw allows an attacker to reach internal resources and cloud metadata, potentially leading to data leakage or privilege escalation.
Recommendation
Update Bulwark Webmail to version 1.9.2 or later and consider blocking requests to private and metadata addresses at the network level.
Other vulnerabilities in Bulwark Webmail
See all- CVE-2026-35391High
In Bulwark Webmail before 1.4.11, the getClientIP() function trusts the first (leftmost) entry of the X-Forwarded-For header, which is fully controlled by the client. An attacker can forge their source IP to bypass IP-based rate limiting (enabling brute-force attacks on the admin login) or forge audit log entries.
- CVE-2026-35390Medium
Bulwark Webmail prior to version 1.4.11 sets the Content-Security-Policy-Report-Only header instead of the enforcing Content-Security-Policy header. This means XSS attacks are logged but not blocked, allowing arbitrary JavaScript execution via crafted email HTML.
- CVE-2026-35389High
In Bulwark Webmail prior to 1.4.11, S/MIME signature verification did not validate the certificate trust chain, so any email signed with a self-signed or untrusted certificate was displayed as having a valid signature.
- CVE-2026-34834High
Bulwark Webmail before version 1.4.10 has a vulnerability in verifyIdentity() that returned true when no session cookies were present. This allows unauthenticated attackers to bypass security and access the /api/settings endpoint, modifying user settings.
- CVE-2026-34833High
Bulwark Webmail prior to version 1.4.10 exposed the user's plaintext password in the JSON response from the GET /api/auth/session endpoint. This exposed credentials to browser logs, local caches, and network proxies.
Original NVD description (English source)
Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.9.2, the unauthenticated POST /api/fetch-ical endpoint validates a caller-supplied hostname with one DNS lookup and then passes the URL to fetch, which performs a separate lookup for the socket connection. An attacker controlling authoritative DNS can return a public address during validation and then rebind the hostname to a loopback, private, link-local, or cloud metadata address for the connection, causing the server to return up to 10 MB of an internal HTTP or HTTPS response. The same check-then-fetch pattern also existed in authenticated JMAP login and TOTP token-exchange flows. This issue is fixed in version 1.9.2.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS