CVE-2026-34559: CI4MS Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4333-387x-w245",
  "modified" : "2026-04-06T17:13:49Z",
  "published" : "2026-04-01T21:53:01Z",
  "aliases" : [ "CVE-2026-34559" ],
  "summary" : "CI4MS: Blogs Tags Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS",
  "details" : "## Summary\n### **Vulnerability: Stored DOM XSS via Blog Tag Name (Persistent Payload Injection)**\n- Stored Cross-Site Scripting via Unsanitized Blog Tag Name in Blog Management\n\n### Description\nThe application fails to properly sanitize user-controlled input when creating or editing blog tags. An attacker can inject a malicious JavaScript payload into the tag name field, which is then stored server-side.\n\nThis stored payload is later rendered unsafely across public tag pages and administrative interfaces without proper output encoding, leading to stored cross-site scripting (XSS).\n\n### Affected Functionality\n- Blog tag creation functionality\n- Blog tag editing functionality\n- Blog tag storage and retrieval logic\n\n### Attack Scenario\n- An attacker creates or edits a blog tag name to include a malicious XSS payload.\n- The application stores this value without sanitization or encoding.\n- The payload persists and executes whenever the tag name is rendered in affected views.\n\n### Impact\n- Persistent Stored XSS\n- Execution of arbitrary JavaScript in victims’ browsers\n- Privilege escalation when viewed by administrators or privileged users\n- Full administrator account takeover\n- Full account takeover across all roles\n- Full compromise of the entire application\n\nEndpoints:\n- `/backend/blogs/tags/`\n- `/blog/{id}`\n\n## Steps To Reproduce (POC)\n1. Go to the Blog Tags management page\n2. Create or edit a tag and insert an XSS payload into the tag name such as:\n`<img src=x onerror=alert(document.domain)>`\n3. Save the tag\n4. View a public blog page or the administrative interface where the tag is rendered\n5. Notice the XSS payload executing automatically\n\n## Remediation\n\n- **Avoid unsafe DOM manipulation methods:** Do not use `.html()`, `innerHTML`, or similar sink functions in client-side JavaScript or server-side templating (e.g., PHP). Even when user input flowing into these sinks is not immediately apparent, they can introduce Cross-Site Scripting (XSS) vulnerabilities that an attacker may exploit.\n\n- **Apply output encoding:** Implement HTML entity encoding on all user-controlled data before rendering it in the browser. This helps neutralize potentially malicious input.\n\n- **Implement input sanitization:** Ensure that all user-supplied input is properly sanitized before processing or output. Currently, no sanitization mechanisms are in place, which should be addressed as a priority.\n\n- **Enforce security headers and cookie attributes:**\n  - **Content Security Policy (CSP):** Define and enforce a strict CSP to limit the execution of unauthorized scripts.\n  - **HttpOnly flag:** Set the `HttpOnly` attribute on session cookies to prevent client-side script access.\n  - **SameSite attribute:** Configure the `SameSite` cookie attribute to mitigate Cross-Site Request Forgery (CSRF) risks.\n  - **Secure flag:** Ensure all cookies are transmitted only over HTTPS by enabling the `Secure` attribute.\n\n  These measures collectively reduce the impact of XSS and help prevent escalation paths such as CSRF via XSS.\n# Ready Video POC:\nhttps://mega.nz/file/GI9Bnbha#FkVY4K7AiuttnBGDFaCtxuJwKk-afRcKjYJnkqfLZOM",
  "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-4333-387x-w245"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34559"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ci4-cms-erp/ci4ms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ci4-cms-erp/ci4ms/releases/tag/0.31.0.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T21:53:01Z",
    "nvd_published_at" : "2026-04-01T22:16:18Z"
  }
}