CVE-2025-56154
📋 TL;DR
htmly v3.0.8 contains a reflected cross-site scripting (XSS) vulnerability in the /author/:name endpoint where the name parameter is not properly sanitized. Attackers can inject malicious JavaScript payloads that execute in victims' browsers when they visit crafted URLs. This affects any htmly v3.0.8 installation with the vulnerable endpoint accessible.
💻 Affected Systems
- htmly
📦 What is this software?
Htmly by Htmly
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, perform actions as authenticated users, redirect to malicious sites, or deploy malware through drive-by downloads.
Likely Case
Session hijacking, credential theft, or defacement of pages viewed by users who click malicious links.
If Mitigated
Limited impact if proper input validation, output encoding, and Content Security Policy (CSP) are implemented.
🎯 Exploit Status
Exploitation requires user interaction (clicking a malicious link). Proof-of-concept available in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v3.0.9
Vendor Advisory: https://github.com/danpros/htmly/releases/tag/v3.0.9
Restart Required: Yes
Instructions:
1. Backup current installation. 2. Download htmly v3.0.9 from GitHub releases. 3. Replace existing files with patched version. 4. Restart web server/service.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side validation to reject malicious characters in the name parameter.
Modify application code to sanitize input before processing.
Web Application Firewall (WAF) Rule
allBlock requests containing JavaScript patterns in the /author endpoint parameters.
Add WAF rule to detect and block XSS payloads in URL parameters.
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to block inline script execution.
- Disable or restrict access to the /author/:name endpoint if not required.
🔍 How to Verify
Check if Vulnerable:
Test by accessing /author/<script>alert('XSS')</script> endpoint and check if script executes.Check Version:
Check htmly version in admin panel or via package manager (e.g., `npm list htmly` if applicable).Verify Fix Applied:
After patching, test same payload; script should not execute and input should be properly encoded.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /author/ endpoint with script tags or JavaScript payloads in URL parameters.
- Unusual spikes in requests to author pages.
Network Indicators:
- Outbound connections to suspicious domains following visits to /author/ pages.
SIEM Query:
source="web_logs" AND url="/author/*" AND (url CONTAINS "<script>" OR url CONTAINS "javascript:")