High 7.5Published Oct 20, 2026

CVE-2026-113728Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint

Updated under an hour ago (Oct 28, 2026, 9:50 AM ET)

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EPSS puts the chance of exploitation in the next 30 days at 0.51%, higher than 43% of scored CVEs.

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Exploited in the last 30 days

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 (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.51% (percentile 43)
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 27, 2026
First seen by InfoSec Signals: Oct 20, 2026

Affected products

Affected products

bulwarkmail webmail bulwarkmail:webmail (from the name)	before 1.9.2	CNA record

References

References

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm	x-refsource-confirm
https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941	x-refsource-misc
https://github.com/bulwarkmail/webmail/releases/tag/1.9.2	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.