fix(security): [CRITICAL] resolve open redirect vulnerability

[Tugamer89]

Severity: CRITICAL

Vulnerability: Open Redirect vulnerability bypass in get_safe_redirect_url. The urllib.parse.urlparse function parses URLs like http:evil.com or http:///evil.com with a valid scheme ('http') but an empty netloc (''). The previous validation logic permitted these URLs because parsed.netloc was empty, thus skipping the strict host match. However, modern browsers interpret such strings as valid absolute URLs and will follow the redirect to external malicious servers, potentially compromising user tokens or performing phishing attacks.

Impact: Attackers can trick users into clicking on malicious links containing crafted next or referer parameters. The application would then redirect users to an attacker-controlled domain under the guise of an authenticated operation.

Fix: Introduced an explicit condition if parsed.scheme and not parsed.netloc: in get_safe_redirect_url to reject URLs missing a netloc if they have a scheme, resolving the validation bypass.

Verification: Verified the fix by invoking get_safe_redirect_url locally against inputs like http:evil.com, http:///evil.com, confirming they now appropriately return /. Lints pass without errors.

---

PR created automatically by Jules for task 3813081336633118368 started by @Tugamer89

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud