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Security report for mastodon.xyz

Mastodon · Technology · France

Medium risk. 3 critical or high findings in GDPR outside view and SSL/TLS.

Security score

65/100

Risk levelMedium

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

Mastodon.xyz operates as an independent Mastodon instance within the federated social networking ecosystem known as the fediverse. It provides an open platform primarily targeting English and French speaking users, offering microblogging and social networking services without ads or algorithms. The website is built on the Mastodon platform version 4.3.4, leveraging modern web technologies including React and WebSockets for real-time interactions. Hosted by OVH in France, the domain is well-established since 2017 and shows consistent registration data, supporting its legitimacy. Security posture is solid with HTTPS and domain transfer protections, though DNSSEC is not enabled and some security headers are missing. Privacy compliance is partial, with a privacy policy present but lacking cookie consent mechanisms and terms of service. No contact information or incident response details are publicly available. Overall, the site presents a professional, community-driven social network with good technical implementation and moderate privacy compliance.

Scanned

NIS2 and GDPR posture

GDPR outside view
53/ 100 · Medium
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

3 findings rated critical or high. Fix these first.

  1. GDPR outside view

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

    • 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

    • High

      No Cookie Consent Banner found

      GDPR requires explicit consent for non-essential cookies

      What to do: Implement a cookie consent banner that appears on first visit

  2. SSL/TLS

    TLS encrypts the connection and proves the site is really yours. Weak or expiring certificates trigger browser warnings and put traffic at risk.

    • High

      Weak SSL Key Length

      SSL certificate uses 256-bit key, which is considered weak

      What to do: Use at least 2048-bit RSA or 256-bit ECC key

      • CWE-326
      • OWASP A04:2025
      • Mozilla TLS: Mozilla Server Side TLS 6.0 intermediate: rsa_key_size 2048

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

Keep watching mastodon.xyz

This scan found 19 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
75
Security headers
75
Email security
70
DNS health
75
Network security
40
GDPR outside view
53
Average
65

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

Technical appendix

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

Business context

Business profile

Mastodon.xyz positions itself as a community-centric social network instance within the decentralized fediverse, competing with other Mastodon servers and federated platforms. Its open registration status is closed, indicating controlled user onboarding. The business model is based on open source software and community participation rather than commercial revenue streams. The target audience includes general users interested in decentralized social media, especially English and French speakers. The platform benefits from the broader Mastodon ecosystem and open source community, with no direct parent or subsidiary companies. The hosting by OVH and domain registration in France align with European data protection norms, though explicit GDPR compliance measures are limited on the site. The platform's trust is supported by transparent domain registration and active user statistics displayed publicly.

Security posture

The website employs HTTPS with a valid SSL certificate and domain status flags that prevent unauthorized domain transfer or deletion, enhancing domain security. However, DNSSEC is not enabled, which could improve DNS security. No explicit security headers such as Content-Security-Policy or X-Frame-Options were detected in the provided data, representing an area for improvement. The absence of a vulnerability disclosure policy or security.txt file limits transparency in security incident handling. No contact channels for security incidents or abuse were found. The site does not expose sensitive data in the HTML content and uses secure modern frameworks. Overall, the security posture is good but could be enhanced by implementing DNSSEC, security headers, and formal incident response policies.

Recommendations

  1. Enable DNSSEC on the domain to improve DNS security and prevent spoofing.
  2. Implement and display a cookie consent mechanism to comply with privacy regulations.
  3. Publish terms of service and a security policy to enhance transparency and legal clarity.
  4. Add security headers such as Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
  5. Provide clear contact information for security incidents and abuse reporting to improve incident response readiness.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Mastodon
Description
A Mastodon instance, open to everyone, but mainly English and French speaking.
Key services
social networking, federated microblogging
Content quality
good
Branding
consistent

Technology

Stack
Ruby on Rails (implied by Mastodon), JavaScript, React (implied by React Helmet tags), WebSockets
Frameworks
Mastodon (4.3.4)
Platforms
fediverse, web
Performance
moderate
Mobile
good
Accessibility
basic
SEO
basic

Security

Observed score
75/100
Good practices seen
  • HTTPS enabled
  • clientTransferProhibited and clientDeleteProhibited domain status

Analytics and tracking

Tracking level
minimal
Privacy practices
basic

Advertising

Transparency
poor

Site quality

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

Key observations

  1. Website is a Mastodon social network instance with active user base.
  2. No explicit privacy or cookie consent banners detected despite privacy policy presence.
  3. No contact emails or phone numbers publicly listed.
  4. No terms of service or security policy pages found.
  5. Website uses modern JavaScript and React-based frontend.
  6. No advertising or tracking scripts detected.
  7. Content is user-generated social posts with diverse topics.
  8. No signs of adult or NSFW content.
  9. WHOIS data supports legitimacy and domain stability.
Technical notes

Notes

The website is built on the Mastodon platform version 4.3.4, utilizing modern JavaScript frameworks including React. It uses WebSockets for streaming API connections, enhancing real-time user experience. Hosting is provided by OVH, a reputable European provider, with domain registration consistent since 2017. The site includes multiple favicon sizes and Apple touch icons, indicating attention to cross-device compatibility. Performance is moderate with preloading and integrity attributes on scripts for security. SEO is basic with meta tags and Open Graph data present, but no advanced structured data like JSON-LD for organization or breadcrumbs. Accessibility is basic with ARIA labels and keyboard navigation support. The site lacks cookie consent and terms of service pages, which are technical and compliance gaps. Overall, the technical infrastructure is solid and modern but could benefit from enhanced SEO and compliance features.
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

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