STACKCURVE
Research & Advisory/CURVE(TM) Reports/Email Security
2026 · CURVE(TM) ReportCyber ResiliencePublished May 20, 2026

Email Security CURVE(TM) Report

The most exploited attack vector in the enterprise - and the vendors finally getting ahead of it.

Email remains the entry point for over 90% of enterprise breaches - and the threat has fundamentally changed. AI-generated phishing, business email compromise, and vendor email fraud have outpaced the legacy secure email gateways built to stop yesterday's attacks. This report maps the vendors moving from reactive filtering to behavioral AI, BEC prevention, and integrated cloud email protection - and identifies who is closing the gap between where attacks are and where defenses are.

No paywall · Contact details required

Key Findings

  • 1Legacy SEGs are failing against AI-generated phishing - the replacement cycle is now underway across regulated industries
  • 2BEC losses exceed ransomware in total annual enterprise cost, yet most email security budgets are sized for the lesser threat
  • 3Cloud-native API-based email protection has fundamentally different detection architecture than gateway-based approaches - they are not equivalent
  • 4Only three vendors have built genuine behavioral AI engines capable of detecting zero-day BEC at enterprise scale
  • 5Integrated cloud email platforms (Microsoft Defender, Google Workspace Security) are closing the capability gap with best-of-breed faster than most buyers have updated their shortlists

Inside the Report

What's covered

01

The Email Threat Has Changed

AI-generated phishing, deepfake voice and video BEC, and vendor email fraud are the new attack patterns. Why legacy SEGs - built for malware attachments and known-bad URLs - are structurally insufficient against the current generation of email threats.

02

The SEG Replacement Cycle

The secure email gateway replacement cycle has begun. This chapter maps the drivers, the timeline, and the enterprise buyer segments moving fastest - and what they're replacing legacy SEGs with.

03

BEC: The Highest-Cost, Lowest-Visibility Threat

Business email compromise now exceeds ransomware in total enterprise financial impact. Why it's so hard to detect, which vendors have built meaningful BEC-specific controls, and the detection architectures that work.

04

Vendor Landscape on the CURVE(TM)

Email security vendors plotted across Capability, Velocity, Readiness, and Ecosystem. Native API-based platforms vs. legacy SEGs vs. AI-native challengers - who is Frontier and who is falling behind.

05

Sourcing Guidance for Enterprise Buyers

How to evaluate email security vendors in 2026: what capabilities to require, what questions expose vendor gaps, and the deployment architecture that maximizes protection for cloud-native email environments.

Who Should Read This

  • CISOs evaluating SEG replacement or augmentation strategies
  • IT Directors responsible for email security and anti-phishing programs
  • Security architects selecting cloud-native email protection platforms
  • Risk officers quantifying BEC and phishing exposure
  • Procurement leaders comparing email security vendors for enterprise refresh cycles

Report Details

Published2026 Edition
PillarCyber Resilience
FormatPDF - Free Download
IndependenceNo pay-for-placement

Free Report

Get the Email Security CURVE(TM)

Enter your contact details - the PDF is yours immediately.

Editorial Firewall

Independent by design. Not pay-for-placement.

No vendor pays to appear in a CURVE(TM) Report, influence a tier, or shape a finding. Reprint rights are the only commercial relationship - purchased after publication, never before. The editorial firewall is the product.

Read the Full Methodology →