Building a Mythos-Ready Security Program: What CISOs Need to Do Now
Jeff Sowell · 2026-04-15 · Industry Analysis
The CSA/SANS 'AI Vulnerability Storm' briefing lays out 13 risks and 11 priority actions. Here's what it means for your GRC practice and how to operationalize it — starting this week.
The briefing every CISO should read today
On April 15, 2026, the Cloud Security Alliance CISO Community, SANS Institute, and the OWASP Gen AI Security Project published an expedited strategy briefing titled "The AI Vulnerability Storm: Building a Mythos-Ready Security Program." It was co-authored by some of the most credentialed security leaders in the industry — Jen Easterly (former CISA Director), Bruce Schneier, Phil Venables (former Google Cloud CISO), Rob Joyce (former NSA Cybersecurity Director), Heather Adkins (Google CISO), and dozens of practicing CISOs from organizations including Atlassian, Cloudflare, NFL, lululemon, 1Password, and Rivian.
This is not a vendor whitepaper. It is a coordinated call to action from the CISO community in response to Anthropic's Claude Mythos and the Project Glasswing vulnerability disclosures.
The core message: the assumptions behind your current security program — patch windows, exploit timelines, risk scoring models, incident frequency estimates — may no longer hold. The time between vulnerability discovery and weaponization has collapsed to hours. Defenders need to recalibrate.
What happened and why it matters
Anthropic's Claude Mythos autonomously discovered thousands of critical vulnerabilities across every major operating system and browser, generated working exploits without human guidance, and demonstrated autonomous attack orchestration at a speed that outpaces any prior capability. In internal testing, Mythos generated 181 working exploits on Firefox where Claude Opus 4.6 succeeded only twice under the same conditions.
Project Glasswing — Anthropic's coordinated disclosure effort — gave 40 major vendors early access to Mythos to patch their products. But as the briefing notes, "the world's exploitable attack surface is vastly larger than what any curated partner ecosystem can cover."
The practical implication: your organization is about to face a sustained increase in critical vulnerability disclosures, shorter exploitation timelines, and more sophisticated automated attacks. This is not a temporary spike — it is a structural shift.
The 13 risks in the Mythos risk register
The briefing includes a draft risk register mapped to NIST CSF 2.0, OWASP LLM Top 10, OWASP Agentic Top 10, and MITRE ATLAS. Here are the risks every security program needs to account for:
Critical severity:
1. Accelerated threat exploitation — AI-autonomous exploit generation at machine speed. Non-frontier models can already do much of this. Mythos is the acceleration, not the starting gun.
2. Insufficient AI automation capabilities — Defenders operating at human speed while attackers operate with AI augmentation. The asymmetry is cultural, not just technological.
3. Unmanaged AI agent attack surface — Privileged AI agents operating outside existing control frameworks. Both internal agents (insecure by default) and third-party agents (supply chain risk).
4. Inadequate incident detection and response velocity — De