CVE-2026-113728

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

CVSS score

7.5

EPSS probability

—

Risk score

0.8

Published

4 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

Impact on My Inventory

Only the personal products you have added to your account are assessed; an organisation's inventory does not appear here.

Checking session…

Vulnerability description

DayBreach AI Explanation

Verified against sources

DNS-Rebinding SSRF Vulnerability in Bulwark Webmail

Sources read

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

Bulwark Webmail prior to version 1.9.2 contains a DNS-rebinding SSRF vulnerability in the unauthenticated POST /api/fetch-ical endpoint.

Why does it matter?

Attackers can exploit this flaw to retrieve internal HTTP or HTTPS responses from the server and gain unauthorized access to sensitive information.

What should be done?

Upgrade to version 1.9.2 or later
Follow vendor advisories for updates

Chain of evidence and sources2 verified claims

Bulwark Webmail 1.9.2 öncesi sürümlerde, kimlik doğrulaması gerektirmeyen POST /api/fetch-ical uç noktasında DNS yeniden bağlama SSRF zafiyeti bulunmaktadır.

S0 · daybreach-canonical S1 · cvelist

Saldırgan doğrulama sırasında genel bir adres döndürüp bağlantı için ana bilgisayar adını dahili bir adrese yeniden bağlayabilir.

S0 · daybreach-canonical S1 · cvelist

Show the technical text from the sources

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 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE: CWE-918

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-113728 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	bulwarkmail	webmail	View

Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
7.5	CVSS V3_1	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	CVE CNA
7.5	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	NVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-113728 is associated with the following CWEs:

CWE-918: Server-Side Request Forgery (SSRF)

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-113728 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwmvendor-advisory https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941vendor-advisory https://github.com/bulwarkmail/webmail/releases/tag/1.9.2vendor-advisory

CVSS Vector Radar Chart

7.5 / 10

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

bulwarkmail

Weakness Type (CWE & CAPEC)

CWE-918