Raw vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-27599 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Ci4-Cms-Erp Ci4Ms. Its CVSS base score is 4.7 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-27599 is a cross-site scripting (XSS) vulnerability, classified under CWE-79, affecting CI4MS, a CodeIgniter 4-based CMS skeleton providing production-ready modular architecture with RBAC authorization and theme support. In versions prior to 0.31.0.0, the application fails to sanitize user-controlled input in the System Settings – Mail Settings section. Fields such as Mail Server, Mail Port, Email Address, Email Password, Mail Protocol, and TLS settings accept attacker input that is stored server-side and later rendered without proper output encoding, enabling stored XSS attacks.
The vulnerability has a CVSS v3.1 base score of 4.7 (AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L), indicating exploitation over the network with low complexity but requiring high privileges (PR:H), such as administrative access. A privileged attacker can inject malicious payloads into the mail configuration fields, which are persisted and rendered unsafely when other users, including admins, view the settings page. This allows limited execution of arbitrary JavaScript in the victim's browser context, potentially leading to low-impact confidentiality, integrity, and availability effects, such as session hijacking or minor data manipulation for authenticated viewers.
The GitHub Security Advisory (GHSA-66m2-v9v9-95c3) confirms the issue has been patched in CI4MS version 0.31.0.0, recommending immediate upgrades to mitigate the vulnerability. Security practitioners should review access controls for mail settings and implement input validation and output encoding as interim defenses.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17199
Vulnerability Data
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,…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.1.2V1.3.2
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.
Input validation directly enforces neutralization of untrusted data before it reaches web output generation.
Output filtering can catch or sanitize unneutralized script content before it is served to users.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).
Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.
Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.
Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.
Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.
Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.