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Glossary Term

Certificate Expiration Risk

Security and availability incidents that arise when SSL/TLS certificates expire on websites or APIs.

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What it is

Every TLS/SSL certificate has a fixed validity period. When it expires, browsers immediately flag the site as insecure or block access altogether. Any internet-facing service—marketing sites, APIs, edge proxies, customer portals, or third-party integrations—can fail if its certificate is out of date or configured without automated renewal.

Why it matters

Expired certificates routinely cause avoidable incidents:

  • Websites and APIs go offline or show full-screen warnings
  • Third-party integrations that rely on mTLS fail silently
  • Customers lose confidence and abandon conversions
  • Incident responders scramble to issue and deploy a new cert under pressure

Because certificate lifetimes continue to shrink (currently 398 days), overlooking renewal windows creates recurring availability and trust issues.

How to reduce risk

  • Maintain an inventory of every certificate across root domains, subdomains, and vendor-managed services
  • Enable automated renewal (ACME, managed PKI, or CDN automation) wherever possible
  • Configure monitoring that alerts well before expiration thresholds (30/15/7 days)
  • Test renewal workflows regularly to ensure new certificates deploy cleanly to all endpoints