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Security report for stumbleupon.com

StumbleUpon · Technology · N/a

Medium risk. 9 critical or high findings in Security headers, GDPR outside view and 2 other checks.

Security score

63/100

Risk levelMedium

0–100, higher is better. How it is calculated

StumbleUpon is a long-established web content discovery platform founded in 2001, offering users personalized web content exploration through a simple 'Stumble!' feature. The website is built using modern web technologies including React and Next.js, hosted on AWS infrastructure, and integrates Google services such as reCAPTCHA Enterprise and Google Tag Manager for security and analytics. The site appears to be transitioning or partnering with Mix.com, as indicated by modal content promoting Mix and related authentication flows. Security posture is generally good with HTTPS enforced and domain protections in place, but lacks published privacy, cookie, and security policies, which impacts compliance and user trust. No contact information or vulnerability disclosure mechanisms are present, limiting transparency. Overall, the site is functional and professional but could improve in privacy compliance and security transparency.

Scanned

NIS2 and GDPR posture

GDPR outside view
35/ 100 · High
Checks completed
7of 7

NIS2 Art. 21(2)

  1. (a) Risk analysis and security policies: Not visible from outside
  2. (b) Incident handling: One indicator
  3. (c) Business continuity, backups and crisis management: Not visible from outside
  4. (d) Supply chain security: Not visible from outside
  5. (e) Secure acquisition, development and maintenance, including vulnerability handling: Partly checked
  6. (f) Assessing the effectiveness of security measures: Not visible from outside
  7. (g) Cyber hygiene and security training: Not visible from outside
  8. (h) Cryptography and encryption: Partly checked
  9. (i) HR security, access control and asset management: One indicator
  10. (j) Multi-factor authentication and secured communications: Not visible from outside

This scan rated NIS2 with an earlier keyword method that is no longer shown; rescan for the per-article view. Risk management, continuity, supply chain, training, MFA, management oversight (Art. 20) and incident reporting (Art. 23) need internal evidence, and Guard cannot tell whether NIS2 applies to this organisation.

GDPR is indicative only, based on publicly visible signals: Articles 7, 12, 13 and 32 of Regulation (EU) 2016/679 and Article 5(3) of the ePrivacy Directive. Not a certification or legal assessment.

Priority findings

9 findings rated critical or high. Fix these first.

  1. Security headers

    Security headers are instructions your web server sends to every visitor’s browser. Missing ones leave visitors more exposed to attacks such as clickjacking and injected scripts.

    • High

      Missing Strict-Transport-Security header

      Forces HTTPS connections

      What to do: Add "Strict-Transport-Security: max-age=31536000; includeSubDomains; preload"

      • CWE-319
      • OWASP A04:2025
      • ASVS V3.4.1
    • High

      Missing X-Frame-Options header

      Prevents clickjacking attacks

      What to do: Add "X-Frame-Options: DENY" or "X-Frame-Options: SAMEORIGIN"

    • High

      Missing Content-Security-Policy header

      Controls resources the browser is allowed to load

      What to do: Implement a Content-Security-Policy appropriate for your application

      • ASVS V3.4.3
      • OWASP Secure Headers: OWASP Secure Headers Project recommends Content-Security-Policy: default-src 'self'; form-action 'self'; base-uri 'self'; object-src 'none';…
  2. GDPR outside view

    These are the privacy signals visitors and data protection authorities look for under GDPR.

    • High

      No Privacy Policy found

      GDPR requires a clear and accessible privacy policy

      What to do: Add a comprehensive privacy policy page and link to it prominently

    • High

      No Cookie Policy found

      GDPR requires clear information about cookie usage

      What to do: Add a dedicated cookie policy explaining cookie usage and purposes

Need hands-on remediation? Email guard@offseq.com

Keep watching stumbleupon.com

This scan found 24 issues across 6 checks. Monitoring re-runs those checks daily, emails you when something material changes and records each fix, so you can show progress.

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  • TLS certificates and expiry
  • DNS records
  • SPF, DKIM and DMARC
  • Security headers
  • GDPR and NIS2 posture
  • Exposed services
  • Third-party trackers
  • Security score drift

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Results by check

Each check with its score, findings and the evidence it collected.

How this score is calculated

The security score runs 0–100, higher is better. It is the plain average of the security checks that completed in this scan, each counted equally. A check that could not run is left out: it counts neither as a pass nor as a fail.

Counted in this score

SSL/TLS
77
Security headers
15
Email security
75
DNS health
75
Network security
100
GDPR outside view
35
Average
63

Not counted

  • NIS2 outside view: Re-weights evidence from the TLS, email, DNS, network and hygiene checks, so counting it would count that evidence twice. Shown on its own.
  • OffSeq Observations: An AI reading of the site, useful context but not reproducible evidence. Shown on its own.

Findings that cap the score at 49

Each of these is serious on its own, so while any is present the site cannot rate better than high risk, however good the other checks are.

  • The certificate is not trusted by browsers
  • The website is not served over HTTPS
  • A database, remote desktop, file-sharing or Telnet service is reachable from the internet
  • The page loads a script from a compromised source
  • The domain registration has expired
  • SPF authorises every server to send mail as the domain

Partial scans

When the site blocks Guard or most checks cannot run, the score covers only the checks that ran (usually DNS and email), is capped at 75 and is shown as partial, without a risk level.

Risk levels

  • Critical0–25
  • High26–49
  • Medium50–75
  • Low76–100

Breach exposure

Leaked credentials and lookalike domains from OffSeq Breach. The counts are free; the detailed lists are paid add-ons.

Dark web exposure

Add-on

Leaked records that mention stumbleupon.com, from OffSeq Breach.

Total records
54,356
Employees
0
Customers
54,291
Third parties
65
Weak passwords
26%

20 subdomains affected

See the 10 newest leaked credentials

A one-off add-on to this report that lists the most recent identifier and password pairs OffSeq Breach holds for stumbleupon.com.

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Breach keeps ingesting new leaks, so these numbers can grow between scans.

Technical appendix

Business context, site observations and technical notes gathered during the scan, and the standards behind each reference.

Business context

Business profile

StumbleUpon operates in the technology sector as a niche content discovery and curation platform targeting general web users interested in personalized content. Its business model centers on user engagement through content recommendation and curation. The domain age and registration details support a legitimate and established presence. The partnership or transition to Mix.com suggests strategic repositioning or brand evolution. The absence of direct contact information and formal policies may limit user trust and regulatory compliance. The platform likely generates revenue through user engagement and possibly advertising or partnerships, though no explicit monetization details are present.

Security posture

The website enforces HTTPS and uses Google reCAPTCHA Enterprise to mitigate automated abuse, indicating a baseline security maturity. Domain registration includes multiple prohibitive statuses to prevent unauthorized transfers or deletions, reflecting good domain management. However, the absence of security headers such as Content-Security-Policy and lack of published security policies or incident response contacts represent gaps in security transparency and defense-in-depth. No vulnerabilities or exposed sensitive data were detected in the analyzed content. The site would benefit from enhanced security headers, formalized security policies, and vulnerability disclosure mechanisms to improve overall security posture and compliance.

Recommendations

  1. Publish comprehensive privacy and cookie policies with GDPR compliance and consent mechanisms.
  2. Implement and publish a security policy including incident response contact information.
  3. Enable DNSSEC to enhance DNS security and prevent spoofing.
  4. Add security headers such as Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
  5. Provide clear company contact information to improve transparency and trust.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
StumbleUpon
Description
StumbleUpon is a web discovery platform that allows users to find and explore web content personalized to their interests, one click at a time.
Key services
Personalized web content discovery, Content curation, User engagement through 'Stumble!' feature
Content quality
good
Branding
consistent

Technology

Stack
React, Next.js, Google reCAPTCHA Enterprise, Google Tag Manager
Frameworks
Next.js
Performance
moderate
Mobile
good
Accessibility
basic
SEO
basic

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • Use of Google reCAPTCHA Enterprise for bot protection
  • Domain status includes multiple prohibitions to prevent unauthorized changes

Analytics and tracking

Services
Google Analytics (implied by Google Tag Manager)
Tracking level
moderate
Privacy practices
poor

Advertising

Transparency
basic

Site quality

Design
good
User experience
good
Content relevance
good
Navigation
good
Professionalism
good
Trustworthiness
moderate

Key observations

  1. Website is accessible with no blocking or WAF challenges.
  2. No explicit privacy, cookie, or terms of service policies found on the homepage HTML content.
  3. Site uses modern JavaScript frameworks and Google services for analytics and bot protection.
  4. No direct company contact emails, phone numbers, or physical addresses found in the HTML content.
  5. Site promotes migration or usage of Mix.com, indicating possible brand transition or partnership.
  6. No security.txt or vulnerability disclosure information found.
  7. No certifications or security frameworks mentioned.
Technical notes

Notes

The website leverages a modern React-based framework (Next.js) with server-side rendering capabilities, improving performance and SEO. Hosting on AWS infrastructure ensures scalability and reliability. Integration with Google services for analytics and bot protection is standard practice. The site shows good mobile optimization and basic accessibility features. However, SEO optimization is basic with limited metadata and no structured data like JSON-LD or Open Graph tags detected. Performance is moderate, likely due to multiple deferred JavaScript chunks. There is an opportunity to improve accessibility and SEO by adding ARIA attributes and richer metadata. Overall, the technical implementation is solid but could be enhanced for better discoverability and user experience.
Standards and sources

Reference chips under each finding point to the standard, regulation or specification the finding relates to. They are taken from the official datasets below and mapped conservatively: a finding with no defensible link shows none. NIS2 and GDPR references mark where a finding is relevant evidence, not a compliance verdict. Implementing Regulation (EU) 2024/2690 binds digital infrastructure and digital service providers; for other entities it is the most detailed public reading of the Article 21 measures. WCAG, EN 301 549, European Accessibility Act and Web Accessibility Directive references name the requirement an automated accessibility rule relates to; they are not a conformance verdict.

Retrieved 2026-10-25

Earlier scans of this domain

  1. 63/100Medium33 findingsView report
  2. 63/100Medium33 findingsView report
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