{"id":"CVE-2026-113728","aliases":["EUVD-2026-105773","GHSA-24w9-8r42-8jwm"],"status":"published","title":"Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint","description":"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.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00507,"percentile":0.43782,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-918"],"published":"2026-10-20T21:12:38Z","modified":"2026-10-29T02:31:11Z","products":[{"vendor":"bulwarkmail","product":"webmail"}],"references":[{"url":"https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/bulwarkmail/webmail/releases/tag/1.9.2","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/113xxx/CVE-2026-113728.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-113728","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-113728","title":"Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint","description":"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.","status":"published","published":"2026-10-20T21:12:38.182Z","modified":"2026-10-27T13:28:01.863Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T13:44:40.64332Z"}],"euvd":[{"id":"EUVD-2026-105773","description":"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.","status":"published","published":"2026-10-20T21:12:38Z","modified":"2026-10-27T13:28:01Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-02T16:59:24.088226Z"}],"nvd":[{"id":"CVE-2026-113728","description":"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.","status":"published","published":"2026-10-20T22:19:29.74Z","modified":"2026-10-27T14:16:33.533Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:13:01.751479Z"}],"osv":[{"id":"CVE-2026-113728","title":"Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint","description":"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.","status":"published","published":"2026-10-20T21:12:38.182Z","modified":"2026-10-29T02:31:11.844286777Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:44:56.310988Z"}]}}