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Security report for prebid.org

Prebid.org · Technology · United States

Medium risk. 5 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

68/100

Risk levelMedium

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

Prebid.org is a leading open source technology provider in the programmatic advertising space, offering a comprehensive suite of header bidding products including Prebid.js, Prebid Server, and Prebid Mobile. The organization operates as a community-driven membership entity, serving publishers, app developers, and TV programmers to optimize ad revenue through unified auctions. Their market position is strong, supported by a broad ecosystem of partners and trusted by major ad tech companies worldwide. Technically, the website is built on WordPress with modern frameworks and hosted on WP Engine with Cloudflare CDN, delivering fast performance and good mobile optimization. Security posture is moderate with valid SSL certificates but lacks modern TLS protocols and advanced security headers. Privacy compliance is good with a comprehensive privacy policy and GDPR adherence, though cookie policy documentation is limited. Overall, the site demonstrates high professionalism, trustworthiness, and technical maturity.

Scanned

This is an earlier scan of prebid.org. View the latest report

NIS2 and GDPR posture

GDPR outside view
43/ 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

5 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 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 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

  3. 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 prebid.org

This scan found 19 issues across 5 checks. Monitoring re-runs those checks daily, emails you when something material changes and records each fix, so you can show progress.

Daily monitoring

Recommended

€25per month

  • 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
50
Security headers
30
Email security
100
DNS health
85
Network security
100
GDPR outside view
43
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

Prebid.org's business model centers on open source software combined with membership and managed services, targeting large and small publishers and ad tech professionals. Their competitive advantage lies in their transparent, configurable, and trusted unified auction solution. Revenue streams likely include membership fees and managed service offerings. The company fosters a robust community with active project management committees, Slack channels, and events, enhancing collaboration and innovation. Partnerships with documentation providers, event platforms, and web development agencies strengthen their ecosystem. Growth indicators include a large number of global instances and a diverse member directory. Strategic observations highlight the importance of expanding security policies and incident response capabilities to maintain trust and compliance.

Security posture

The current security maturity level is moderate. The website employs standard security headers like X-Frame-Options and secure cookie attributes but lacks enforcement of modern TLS protocols (TLS 1.2 or higher) and HSTS policies. No DNSSEC or CAA records are configured, which could improve domain security. There is no publicly disclosed security policy or incident response plan, and no security.txt file for vulnerability disclosure. The absence of explicit contact channels for security incidents limits incident response readiness. Data protection practices appear aligned with GDPR through a comprehensive privacy policy. The security culture is implied through open source transparency but could benefit from formalized policies and enhanced technical controls. Business impact of current gaps includes potential exposure to SSL downgrade attacks and reduced trust from security-conscious users.

Recommendations

  1. Enable and enforce TLS 1.2 or higher protocols to secure data in transit.
  2. Implement HTTP Strict Transport Security (HSTS) with includeSubDomains and preload directives.
  3. Configure DNSSEC and CAA records to enhance domain name system security.
  4. Publish a security.txt file and establish a clear vulnerability disclosure policy.
  5. Develop and publicly share a formal security policy and incident response plan.

Contact details published on the site

Addresses
Legal name
Prebid.org
Technical notes

Notes

The website infrastructure is robust, leveraging WordPress CMS with Genesis Framework and Mai Engine theme, hosted on WP Engine with Cloudflare CDN for performance and reliability. The technology stack includes JavaScript libraries such as FontAwesome, Swiper Carousel, Vimeo Player, and HubSpot forms for marketing and analytics. Performance is fast with good mobile optimization and accessibility. Technical debt is minimal with modern fonts and SEO plugins like Yoast SEO. Opportunities exist to modernize SSL/TLS configurations and enhance security headers. Technical risks include lack of TLS 1.2+ support and missing DNS security features, which could impact business operations if exploited.
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. 75/100 +2Medium28 findingsView report
  2. 73/100Medium29 findingsView report
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