---
id: CVE-2026-100718
title: >-
  Froxlor through 2.3.10 does not enforce the mail.allow_external_domains policy
  in the EmailSender.add API command
summary: >-
  Froxlor through 2.3.10 does not enforce the mail.allow_external_domains policy
  in the EmailSender.add API command. When an administrator has enabled the
  allowed-sender feature but disabled external allowed-sender domains
  (mail.enable_all…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N'
cwe:
  - CWE-276
vendor: froxlor
product: froxlor
affected:
  - froxlor < 2.3.12
published: '2026-09-26'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T14:16:58.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100718'
references:
  - url: 'https://github.com/froxlor/froxlor/security/advisories/GHSA-m9j6-9856-68xf'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/froxlor-before-2.3.12-authentication-bypass-via-emailsender-add
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-26T13:33:20.891Z'
---

## Overview

Froxlor through 2.3.10 does not enforce the mail.allow_external_domains policy in the EmailSender.add API command. When an administrator has enabled the allowed-sender feature but disabled external allowed-sender domains (mail.enable_allow_sender = 1, mail.allow_external_domains = 0), an authenticated customer with API access can still use EmailSender.add to register an arbitrary external sender address for their mailbox, which is stored despite the policy. This creates a bypass between the UI/administrator configuration and the API, and — where the generated mail configuration consumes the allowed-sender table — allows a customer to authorize sender identities outside their hosted domains, facilitating sender spoofing. Fixed in 2.3.12.

## Remediation

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