---
title: "CVE-2026-27599: ci4-cms-erp/ci4ms: System Settings (Mail Settings) Full Platform Compromise & Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS"
url: https://erroneo.us/security/cve/CVE-2026-27599/
description: "CVE-2026-27599 (ci4-cms-erp/ci4ms (Composer (PHP))): CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-30
date_modified: 2026-04-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-27599"
kev: false
cvss: 4.7
epss: 0.00423
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-27599: ci4-cms-erp/ci4ms: System Settings (Mail Settings) Full Platform Compromise & Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4% , percentile 36: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 36% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes ci4-cms-erp/ci4ms (Composer (PHP)) <= 0.28.6.0, fixed in 0.31.0.0 . Check your lockfile, including transitive dependencies.

## What it is

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.0.0, the application fails to properly sanitize user-controlled input within System Settings – Mail Settings. Several configuration fields, including Mail Server, Mail Port, Email Address, Email Password, Mail Protocol, and TLS settings, accept attacker-controlled input that is stored server-side and later rendered without proper output encoding. This issue has been patched in version 0.31.0.0.

## Affected packages

- Composer (PHP) `ci4-cms-erp/ci4ms` <= 0.28.6.0 → fixed: 0.31.0.0

## Affected products (CVE record)

- ci4-cms-erp ci4ms: < 0.31.0.0

## Severity

- GitHub_M CVSS 3.1: 4.7 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.42% probability of exploitation activity in the next 30 days; percentile 36.

## Sources

- [GitHub Advisory GHSA-66m2-v9v9-95c3](https://github.com/advisories/GHSA-66m2-v9v9-95c3)
- [CVE.org record CVE-2026-27599](https://www.cve.org/CVERecord?id=CVE-2026-27599)
- [NVD entry CVE-2026-27599](https://nvd.nist.gov/vuln/detail/CVE-2026-27599)
- [github.com](https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-66m2-v9v9-95c3)
- [mega.nz](https://mega.nz/file/KRNhUI6Q#NGC3Bow3RlnmdU1H2bGu1BGbpfIc-awi6IlvTp08V1s)

---
Source page: https://erroneo.us/security/cve/CVE-2026-27599/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt