CVE-2026-113728
CVE-2026-113728 · Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 7.5 · High · EPSS 0.5%
- Published
- Updated
Affected products and versions
webmail
- Versions
- < 1.9.2: Affected
No fix published