CVE-2025-28102
📋 TL;DR
A stored cross-site scripting (XSS) vulnerability in flaskBlog v2.6.1 allows attackers to inject malicious scripts into blog posts via the postContent parameter. This affects all users running the vulnerable version of flaskBlog, potentially compromising visitors who view the malicious posts.
💻 Affected Systems
- flaskBlog
📦 What is this software?
Flaskblog by Dogukanurker
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, redirect users to malicious sites, perform actions on behalf of authenticated users, or install malware on visitor systems.
Likely Case
Session hijacking, credential theft, defacement of blog content, or redirection to phishing sites.
If Mitigated
Limited impact with proper input validation and output encoding, though some functionality disruption may occur.
🎯 Exploit Status
Exploitation requires ability to create or edit posts (typically authenticated). Proof-of-concept available in GitHub issues.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Check GitHub repository for updates. 2. Apply input validation and output encoding. 3. Consider migrating to a maintained fork if available.
🔧 Temporary Workarounds
Input Validation Filter
allAdd server-side input validation to sanitize postContent parameter
Implement HTML escaping in Flask templates using {{ content|safe }} only when content is trusted, or use libraries like bleach for sanitization
Content Security Policy
allImplement CSP headers to restrict script execution
Add 'Content-Security-Policy: default-src 'self'; script-src 'self'' to HTTP responses
🧯 If You Can't Patch
- Disable post creation/editing functionality
- Implement WAF rules to block XSS payloads in postContent parameter
🔍 How to Verify
Check if Vulnerable:
Test by creating a post with <script>alert('XSS')</script> in postContent and check if script executes when viewing postCheck Version:
Check flaskBlog version in application configuration or package metadataVerify Fix Applied:
Repeat test with same payload; script should not execute and should be displayed as plain text📡 Detection & Monitoring
Log Indicators:
- Unusual post creation patterns
- POST requests to /createpost with script tags or JavaScript in parameters
Network Indicators:
- HTTP requests containing script tags in postContent parameter
SIEM Query:
source="web_logs" AND uri_path="/createpost" AND (postContent CONTAINS "<script>" OR postContent CONTAINS "javascript:")