vulnerability / NVI-00018544 / Revision 1
changedetection.io Vulnerable to Authentication Bypass via Decorator Ordering
GitHub lists this reviewed advisory for changedetection.io. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.8 critical
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
changedetection.io
source listed<= 0.54.7
### Summary On 13 routes across 5 blueprint files, the `@login_optionally_required` decorator is placed **before** (outer to) `@blueprint.route()` instead of after it. In Flask, `@route()` must be the outermost decorator because it registers the function it receives. When the order is reversed, `@route()` registers the **original undecorated function**, and the auth wrapper is never in the call chain. This silently disables authentication on these routes. The developer correctly uses the decorator on 30+ other routes with the proper order, making this a classic consistency gap. ### Details **Correct order (used on 30+ routes):** ```python @blueprint.route('/settings', methods=['GET']) @login_optionally_required def settings(): ... ``` **Incorrect order (13 vulnerable routes):** ```python @login_optionally_required # ← Applied to return value of @route, NOT the view @blueprint.route('/backups/download/') # ← Registers raw function def download_backup(filename): ... ``` ## POC ``` === PHASE 1: Confirm Authentication is Required === $ curl -s -o /dev/null -w "%{http_code}" http://127.0.0.1:5557/ Main page: HTTP 302 -> http://127.0.0.1:5557/login?
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-jmrh-xmgh-x9j4 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.