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Security report for mastodon.art

Mastodon.ART · Technology · United States

Medium risk. 4 critical or high findings in GDPR outside view and SSL/TLS.

Security score

68/100

Risk levelMedium

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

Mastodon.ART is a mature, community-driven Mastodon instance established in 2017, focused on providing a safe, inclusive, and ad-free social media platform for creatives and artists. It operates on the fediverse, leveraging Mastodon's open-source technology, and is hosted by Masto.host. The platform emphasizes strong moderation policies, a zero-tolerance stance on hate speech, and prohibits AI-generated content and NFTs to maintain community integrity. The business model relies on community donations rather than advertising or data monetization. Technically, the website runs Mastodon version 4.3.8 with modern TLS protocols (TLS 1.3 and 1.2) and has proper DNS configurations including SPF and DMARC for email authentication. The site performance is moderate with a page load time of approximately 6.8 seconds and good mobile optimization. However, some security enhancements such as enabling HSTS, OCSP stapling, and certificate transparency compliance are recommended. From a security perspective, the site has a solid foundation with HTTPS and email authentication but lacks advanced security headers and published incident response or vulnerability disclosure policies. Privacy compliance is strong with a comprehensive privacy policy and no tracking or ads, though no cookie consent mechanism is present. The domain registration is consistent and trustworthy, with no suspicious patterns detected. Overall, Mastodon.ART presents a trustworthy, well-managed community platform with room for technical and security improvements to enhance user trust and resilience against threats.

Scanned

This is an earlier scan of mastodon.art. View the latest report

NIS2 and GDPR posture

GDPR outside view
40/ 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

4 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 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

    • 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 384-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.art

This scan found 18 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
67
Security headers
75
Email security
50
DNS health
75
Network security
100
GDPR outside view
40
Average
68

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.ART occupies a niche market within the fediverse as a specialized Mastodon instance catering to creatives and artists seeking a safe and ad-free social media environment. Its competitive advantage lies in its strict moderation policies, community ownership, and clear stance against AI-generated content and NFTs, differentiating it from other instances. Revenue streams are primarily donation-based through platforms like LiberaPay, Ko-Fi, and Patreon, reflecting a non-commercial, community-supported business model. The target customer segment includes diverse creative professionals and hobbyists valuing privacy and inclusivity. The partnership with Masto.host for hosting services supports operational stability. Growth indicators include a mature domain age and active user base (~4K monthly active users). Strategic observations suggest focusing on enhancing security posture and formalizing incident response to strengthen community trust and compliance.

Security posture

Mastodon.ART demonstrates a moderate security maturity level with HTTPS enforced via TLS 1.3 and 1.2, SPF and DMARC email authentication, and clientTransferProhibited domain status. No critical vulnerabilities or SSL issues were detected. However, the absence of HSTS, OCSP stapling, certificate transparency compliance, and advanced security headers indicates areas for improvement. The lack of published security policies, incident response contacts, and vulnerability disclosure mechanisms limits transparency and preparedness. Privacy practices are strong, with no tracking or ads and a comprehensive privacy policy. The security culture is community-focused with strict moderation and zero tolerance for hate speech. Business impact of current gaps is moderate, with recommendations to implement missing security controls and formalize policies to reduce risk and enhance compliance.

Recommendations

  1. Enable HTTP Strict Transport Security (HSTS) with includeSubDomains and preload to enforce HTTPS and prevent downgrade attacks.
  2. Implement OCSP stapling to improve SSL certificate revocation checking and reduce latency.
  3. Achieve certificate transparency compliance to enhance trust and detect certificate mis-issuance.
  4. Publish a security.txt file and vulnerability disclosure policy to facilitate responsible reporting and incident response.
  5. Add additional security headers such as Content-Security-Policy, X-Frame-Options, and X-Content-Type-Options to mitigate common web attacks.
Technical notes

Notes

The website is built on Mastodon 4.3.8, utilizing a React frontend and standard web technologies. Hosting is provided by Masto.host, a specialized Mastodon hosting provider. The site uses modern TLS protocols ensuring encrypted communications. Performance is moderate with a page load time of approximately 6.8 seconds and 55 resources loaded, indicating potential optimization opportunities. Mobile optimization and accessibility are good, with responsive design and accessibility features present. SEO is well addressed with proper meta tags and Open Graph data. No CMS detected, indicating a custom or framework-based implementation. Technical risks include lack of advanced security headers and missing OCSP stapling, which could impact security and user trust. Modernization opportunities include performance tuning and enhanced security configurations.
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. 68/100 −1Medium31 findingsView report
  2. 69/100 +1Medium30 findingsView report
  3. 68/100Medium26 findingsView report
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