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CRITICAL severity

CVE-2026-34567 ci4-cms-erp/ci4ms

CRITICAL

CVE-2026-34567 is a critical-severity (CVSS 9.1) Cross-site Scripting (XSS) vulnerability in ci4-cms-erp/ci4ms. A fix is available for ci4-cms-erp/ci4ms — see the affected versions and patch details below.

CI4MS: Blogs Posts (Categories) Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

Also known asGHSA-r33w-c82v-x5v7
Published
Apr 1, 2026
Updated
Aug 12, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs19th percentile — riskier than 19% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2026-34567 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐘ci4-cms-erp/ci4ms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Vulnerability: Blogs Posts (Categories) Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

  • Stored Cross-Site Scripting via Unsanitized Blog Post Content in Blog Management (Categories)

Description

The application fails to properly sanitize user-controlled input when creating or editing blog posts within the Categories section. An attacker can inject a malicious JavaScript payload into the Categories content, which is then stored server-side.

This stored payload is later rendered unsafely when the Categories are viewed via blog posts, without proper output encoding, leading to stored cross-site scripting (XSS).

Affected Functionality

  • Blog post Categories creation functionality
  • Blog post Categories editing functionality
  • Blog post Categories storage and retrieval logic

Attack Scenario

  • An attacker creates or edits a blog post Category to include a malicious XSS payload in the category description or name.
  • The application stores this content without sanitization or encoding.
  • The payload persists and executes whenever the category is viewed within the blog posts section, leading to the execution of arbitrary JavaScript in the victim’s browser.

Impact

  • Persistent Stored XSS
  • Execution of arbitrary JavaScript in victims’ browsers
  • Privilege escalation when viewed by administrators or privileged users within the Categories functionality
  • Full administrator account takeover through Categories access
  • Full account takeover across all roles via Categories pages
  • Full compromise of the entire application via XSS in Categories

Endpoints:

  • /backend/blogs/create (Categories specific)
  • /backend/blogs/ (Categories view)
  • /blog/{id} (Rendered blog post under Categories)

Steps To Reproduce (POC)

  1. Go to the Categories section of the blog management panel.
  2. Create a new category or edit an existing category.
  3. Insert an XSS payload into the category content, such as: <img src=x onerror=alert(document.domain)>
  4. Save or publish the Categories.
  5. View the category via the blog posts in the administrative panel or public blog page under the Categories section.
  6. Notice the XSS payload executing automatically when the Category is viewed in the Blog Posts.

Remediation

  • 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.

  • Apply output encoding: Implement HTML entity encoding on all user-controlled data before rendering it in the browser. This helps neutralize potentially malicious input.

  • 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.

  • Enforce security headers and cookie attributes:

    • Content Security Policy (CSP): Define and enforce a strict CSP to limit the execution of unauthorized scripts.
    • HttpOnly flag: Set the HttpOnly attribute on session cookies to prevent client-side script access.
    • SameSite attribute: Configure the SameSite cookie attribute to mitigate Cross-Site Request Forgery (CSRF) risks.
    • Secure flag: Ensure all cookies are transmitted only over HTTPS by enabling the Secure attribute.

    These measures collectively reduce the impact of XSS and help prevent escalation paths such as CSRF via XSS.

Ready Video POC:

https://mega.nz/file/SAdVxK7b#kFW_sFOim_d_1AnVcpwvzOEV4MHv33LLooL4Xa_Ymgg

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistci4-cms-erp/ci4msall versions0.31.0.0composer require ci4-cms-erp/ci4ms:^0.31.0.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ci4-cms-erp/ci4ms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update ci4-cms-erp/ci4ms to 0.31.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34567 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-34567 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-34567. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Summary ### **Vulnerability: Blogs Posts (Categories) Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS** - Stored Cross-Site Scripting via Unsanitized Blog Post Content in Blog Management (Categories) ### Description The application fails to properly sanitize user-controlled input when creating or editing blog posts within the **Categories** section. An attacker can inject a malicious JavaScript payload into the **Categories** content, which is then stored server-side. This stored payload is later rendered unsafely when the **Categories** are viewed via blog
O3 Security · Impact-Aware SCA

Is CVE-2026-34567 in your dependencies?

O3 Security finds CVE-2026-34567 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-34567: ci4-cms XSS (Critical 9.1) | O3 Security