CVE-2026-25527
📋 TL;DR
This vulnerability in changedetection.io allows unauthenticated attackers to read application source files through a directory traversal flaw in the static file serving route. Anyone running changedetection.io versions before 0.53.2 is affected. The issue enables local file read of sensitive application files.
💻 Affected Systems
- changedetection.io
📦 What is this software?
Changedetection by Webtechnologies
⚠️ Risk & Real-World Impact
Worst Case
Attackers could read sensitive configuration files, source code containing secrets, or other critical files, potentially leading to further exploitation or data exposure.
Likely Case
Unauthenticated file read of application source code, which could reveal implementation details, configuration, or potentially sensitive information.
If Mitigated
Limited impact with proper network segmentation and access controls, though source code exposure still poses some risk.
🎯 Exploit Status
The vulnerability is simple to exploit via crafted HTTP requests to the static file route.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.53.2
Vendor Advisory: https://github.com/dgtlmoon/changedetection.io/security/advisories/GHSA-9jj8-v89v-xjvw
Restart Required: Yes
Instructions:
1. Update changedetection.io to version 0.53.2 or later. 2. Restart the application. 3. Verify the fix by checking the version.
🔧 Temporary Workarounds
Network Access Restriction
linuxRestrict network access to the changedetection.io instance to trusted IPs only.
Use firewall rules to limit access: iptables -A INPUT -p tcp --dport <PORT> -s <TRUSTED_IP> -j ACCEPT
iptables -A INPUT -p tcp --dport <PORT> -j DROP
🧯 If You Can't Patch
- Deploy a reverse proxy or WAF with path validation to block directory traversal attempts.
- Isolate the changedetection.io instance in a restricted network segment with no internet exposure.
🔍 How to Verify
Check if Vulnerable:
Check if version is below 0.53.2. Attempt to access /static/../flask_app.py and see if source code is returned.Check Version:
Check the application interface or deployment logs for version information.Verify Fix Applied:
After updating to 0.53.2+, attempt the same request; it should return an error or not expose files.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /static/../ paths
- Unusual file access patterns in application logs
Network Indicators:
- HTTP requests with directory traversal sequences in the URL path
SIEM Query:
web.url:*\/static\/\.\.\/* OR web.url:*%2e%2e%2f*