GHSA-4333-387x-w245

## Summary ### **Vulnerability: Stored DOM XSS via Blog Tag Name (Persistent Payload Injection)** - Stored Cross-Site Scripting via Unsanitized Blog Tag Name in Blog Management

### Description The 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.

This stored payload is later rendered unsafely across public tag pages and administrative interfaces without proper output encoding, leading to stored cross-site scripting (XSS).

### Affected Functionality - Blog tag creation functionality - Blog tag editing functionality - Blog tag storage and retrieval logic

### Attack Scenario - An attacker creates or edits a blog tag name to include a malicious XSS payload. - The application stores this value without sanitization or encoding. - The payload persists and executes whenever the tag name is rendered in affected views.

### Impact - Persistent Stored XSS - Execution of arbitrary JavaScript in victims’ browsers - Privilege escalation when viewed by administrators or privileged users - Full administrator account takeover - Full account takeover across all roles - Full compromise of the entire application

Endpoints: - `/backend/blogs/tags/` - `/blog/{id}`

## Steps To Reproduce (POC) 1. Go to the Blog Tags management page 2. Create or edit a tag and insert an XSS payload into the tag name such as: `<img src=x onerror=alert(document.domain)>` 3. Save the tag 4. View a public blog page or the administrative interface where the tag is rendered 5. Notice the XSS payload executing automatically

## 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/GI9Bnbha#FkVY4K7AiuttnBGDFaCtxuJwKk-afRcKjYJnkqfLZOM