---
id: CVE-2026-113728
title: 'Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint'
summary: >-
  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 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-918
vendor: bulwarkmail
product: webmail
affected:
  - webmail < 1.9.2
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T21:12:38.182Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-113728'
references:
  - url: >-
      https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm
    label: >-
      https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm
  - url: >-
      https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941
    label: >-
      https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941
  - url: 'https://github.com/bulwarkmail/webmail/releases/tag/1.9.2'
    label: 'https://github.com/bulwarkmail/webmail/releases/tag/1.9.2'
tags:
  - cve.org
ingestedAt: '2026-10-20T21:19:21.147Z'
---

## Overview

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.

## Affected

- `webmail < 1.9.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.