Security headers · the EU (domains)

What share of domains in the EU have no HSTS or Content-Security-Policy header?

86.41%

86.41% of domains in the EU (95% CI 80.71–90.62%), measured across 184 domains on 2026-08-13.

strong: 13.59%partial: 23.37%missing: 63.04%
strong · 13.59%partial · 23.37%missing · 63.04%
Trend

Measured every Thursday since 2026-08-01 — 6 observations to date. Last measured 2026-08-13.

How this is measured

Tier 3a; check Strict-Transport-Security, Content-Security-Policy, X-Frame-Options on the homepage response. Denominator: has_web.

Passive measurement: a single DNS lookup, TLS handshake, or homepage GET per domain. Aggregate-only; no individual company is named. 95% Wilson confidence intervals. Population: domains sampled from the Common Crawl web graph, filtered to those that do email. Parked domains excluded. Snapshot: common-crawl-domain-stratified-c400-g2500-seed20260729.

Licensed CC BY 4.0 — reuse with attribution to Quiet Failures. Download: JSON · CSV.

Why it matters

HSTS is what stops the first, downgradeable request; CSP is what limits the damage of injected script. Both are one-line changes, and both are commonly switched off silently by a framework upgrade or a proxy change.

The same check, other segments

Show the remaining 65 segments

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