CVE-2026-34557: CI4MS Cross-Site Scripting Vulnerability

CRITICAL
Advisory Identifier: GHSA-rpjr-985c-qhvm
CVSS 9.1
CWE-79
Published
Advisory Summary

CVE-2026-34557 is a CRITICAL (CVSS 9.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting CI4MS libraries in the Packagist ecosystem. The issue involves permissions management full account takeover for all-roles & privilege-escalation via stored dom xss. Remediation is available by upgrading affected packages to version 0.31.0.0.

CVE-2026-34557 at a Glance

CVE Identifier CVE-2026-34557
GHSA Identifier GHSA-rpjr-985c-qhvm
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product CI4MS
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-34557

To remediate this vulnerability, upgrade all affected CI4MS dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ci4-cms-erp/ci4ms fixed: 0.31.0.0
Upgrade ci4-cms-erp/ci4ms to 0.31.0.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for ci4-cms-erp/ci4ms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-34557, inspect your project dependencies for CI4MS:

inspect dependencies for ci4-cms-erp/ci4ms

Analyze the terminal output to locate any version of CI4MS in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.31.0.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In CI4MS, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary ### **Vulnerability: Stored DOM XSS via Group / Role Management Fields (Administrative Context Execution)** - Stored Cross-Site Scripting via Unsanitized Group / Role Management Inputs ### Description The application fails to properly sanitize user-controlled input within group and role management functionality. Multiple input fields (three distinct group-related fields) can be injected with malicious JavaScript payloads, which are then stored server-side. These stored payloads are later rendered unsafely within privileged administrative views without proper output encoding, leading to stored cross-site scripting (XSS) within the role and permission management context. ### Affected Functionality - Group creation and editing functionality - Role and permission assignment interfaces - Storage and retrieval of group-related data ### Attack Scenario - An attacker injects a malicious XSS payload into one or more group-related input fields. - The application stores these values without sanitization or encoding. - An administrator views the group or role management interface. - The payload executes automatically in the administrator’s browser. ### Impact - Persistent Stored XSS - Execution of arbitrary JavaScript in victims’ browsers - Privilege escalation when viewed by administrators - Full administrator account takeover - Full compromise of the entire application Endpoints: - `/backend/users/groupList/` ## Steps To Reproduce (POC) 1. Navigate to the Group / Role Management page 2. Insert an XSS payload into any of the three group-related input fields such as: `<img src=x onerror=alert(document.domain)>` 3. Save the group or role changes 4. View the group/role management page as an administrator 5. Observe the XSS payload executing automatically ## Remediation - Never use .html() again or any innerHTML-style like JS in your PHP, or any other sink, even if user inputs that flow into them are not clear, they still represent real world danger as an attacker can make use of this to exploit the application via XSS. And do HTML Encoding as much as possible and always do Sanitization, theres no sanitization there unfortunately. Also apply CSP, HttpOnly, SameSite, and Secure upon all application, they reduce severity of XSS & escalated-CSRF via XSS and do great jobs # Ready Video POC: https://mega.nz/file/6QUEXDbR#JXzYXg9bef_NeSUVFB4R03UeXLtAVtYwTRsdrHLlokU

CVE-2026-34557 Affected CI4MS Versions

1 component(s)
Fixed Versions:
0.31.0.0
Product / Package Ecosystem Affected Versions Fixed Version
ci4-cms-erp/ci4ms
Packagist
< 0.31.0.0
0.31.0.0

References

Frequently Asked Questions

What is CVE-2026-34557?
CVE-2026-34557 is a security vulnerability in CI4MS involving Permissions Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which CI4MS versions are affected?
Affected versions include releases prior to 0.31.0.0 across affected packages: ci4-cms-erp/ci4ms.
What version fixes CVE-2026-34557?
Upgrading to 0.31.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ci4-cms-erp/ci4ms affected?
Yes, ci4-cms-erp/ci4ms is affected in releases prior to 0.31.0.0. Upgrade your dependency to 0.31.0.0 or later.
What is the CVSS score of CVE-2026-34557?
CVE-2026-34557 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L.
What CWE is associated with CVE-2026-34557?
CVE-2026-34557 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-34557?
Run the dependency tree command: 'inspect dependencies for ci4-cms-erp/ci4ms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rpjr-985c-qhvm",
  "modified" : "2026-04-01T00:10:00Z",
  "published" : "2026-04-01T00:10:00Z",
  "aliases" : [ "CVE-2026-34557" ],
  "summary" : "CI4MS: Permissions Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS",
  "details" : "## Summary\n### **Vulnerability: Stored DOM XSS via Group / Role Management Fields (Administrative Context Execution)**\n- Stored Cross-Site Scripting via Unsanitized Group / Role Management Inputs\n\n### Description\nThe application fails to properly sanitize user-controlled input within group and role management functionality. Multiple input fields (three distinct group-related fields) can be injected with malicious JavaScript payloads, which are then stored server-side.\n\nThese stored payloads are later rendered unsafely within privileged administrative views without proper output encoding, leading to stored cross-site scripting (XSS) within the role and permission management context.\n\n### Affected Functionality\n- Group creation and editing functionality\n- Role and permission assignment interfaces\n- Storage and retrieval of group-related data\n\n### Attack Scenario\n- An attacker injects a malicious XSS payload into one or more group-related input fields.\n- The application stores these values without sanitization or encoding.\n- An administrator views the group or role management interface.\n- The payload executes automatically in the administrator’s browser.\n\n### Impact\n- Persistent Stored XSS\n- Execution of arbitrary JavaScript in victims’ browsers\n- Privilege escalation when viewed by administrators\n- Full administrator account takeover\n- Full compromise of the entire application\n\nEndpoints:\n- `/backend/users/groupList/`\n\n## Steps To Reproduce (POC)\n1. Navigate to the Group / Role Management page\n2. Insert an XSS payload into any of the three group-related input fields such as:\n`<img src=x onerror=alert(document.domain)>`\n3. Save the group or role changes\n4. View the group/role management page as an administrator\n5. Observe the XSS payload executing automatically\n\n## Remediation\n- Never use .html() again or any innerHTML-style like JS in your PHP, or any other sink, even if user inputs that flow into them are not clear, they still represent real world danger as an attacker can make use of this to exploit the application via XSS. And do HTML Encoding as much as possible and always do Sanitization, theres no sanitization there unfortunately. Also apply CSP, HttpOnly, SameSite, and Secure upon all application, they reduce severity of XSS & escalated-CSRF via XSS and do great jobs\n\n# Ready Video POC:\nhttps://mega.nz/file/6QUEXDbR#JXzYXg9bef_NeSUVFB4R03UeXLtAVtYwTRsdrHLlokU",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "ci4-cms-erp/ci4ms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.31.0.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.28.6.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-rpjr-985c-qhvm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34557"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ci4-cms-erp/ci4ms"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T00:10:00Z",
    "nvd_published_at" : "2026-03-30T21:17:10Z"
  }
}