---
title: "Anthropic Releases Claude Mythos Preview with Cybersecurity Capabilities"
url: https://stacklist.com/card/f1d55915-dd93-4394-8b1e-c1ba16bd69da
source_url: "https://www.infoq.com/news/2026/04/anthropic-claude-mythos/"
stack: https://stacklist.com/c/finance/stack/d1cd80b1-4423-450f-aa1e-dd4f2fcd5782
summary: "Anthropic has released Claude Mythos Preview, its most capable frontier model featuring dramatic cybersecurity capabilities including autonomous zero-day vulnerability discovery, but has withheld public access in favor of a restricted consortium called Project Glasswing. The initiative brings together major technology companies like AWS, Apple, Google, and Microsoft with $100M in usage credits to identify and patch vulnerabilities in critical software."
tags: "anthropic, claude-mythos, cybersecurity, ai-safety, vulnerability-discovery, project-glasswing, frontier-model"
key_entities: "Anthropic (organization), Claude Mythos Preview (technology), Project Glasswing (event), Claude Opus 4.6 (technology), Daniel Curtis (person), AWS (organization), Apple (organization), Google (organization), Microsoft (organization), CrowdStrike (organization), Palo Alto Networks (organization), NVIDIA (organization), JPMorgan Chase (organization), Linux Foundation (organization), Cisco (organization), zero-day vulnerability discovery (concept), SWE-bench (technology), OSS-Fuzz (technology), InfoQ (organization), OpenBSD (technology), FFmpeg (technology)"
classification: "news"
content_hash: "sha256:e4a685ac469824e6a4a353fe09d98b3f88a0fca2485c59393e18ea21ef42ea33"
acp_version: "0.2"
token_counts_approximate: 1393
visibility: public
agent_accessible: true
status: "final"
---

# Anthropic Releases Claude Mythos Preview with Cybersecurity Capabilities

InfoQ Homepage News Anthropic Releases Claude Mythos Preview with Cybersecurity Capabilities but Withholds Public Access AI, ML & Data Engineering Anthropic Releases Claude Mythos Preview with Cybersecurity Capabilities but Withholds Public Access Apr 13, 2026 2 min read by Daniel Curtis Write for InfoQ Feed your curiosity. Help 550k+ global senior developers each month stay ahead. Get in touch Listen to this article -  0:00 Audio ready to play Your browser does not support the audio element. 0:00 0:00 Normal 1.25x 1.5x Like Reading list Anthropic , the company behind Claude, has released Claude Mythos Preview , its most capable frontier model to date, with dramatic improvements in reasoning, coding, and cybersecurity. In an unusual move, the company has chosen not to make the model generally available, instead restricting access to a consortium of technology companies through a new initiative called Project Glasswing . Claude Mythos Preview represents what Anthropic describes as a "step change" over its predecessor, Claude Opus 4.6. During internal testing, the model autonomously discovered and exploited zero-day vulnerabilities in every major operating system and web browser. The oldest it found was a now-patched 27-year-old bug in OpenBSD, a system known primarily for its security. It also found a 16-year-old vulnerability in FFmpeg's H.264 codec. Internal benchmarks showed dramatic gains. Where Opus 4.6 developed working JavaScript shell exploits only twice out of several hundred attempts on Firefox vulnerabilities, Mythos Preview succeeded 181 times. On the OSS-Fuzz corpus, it achieved full control flow hijack on ten separate, fully patched targets. Engineers at Anthropic with no formal security training asked the model to find remote code execution vulnerabilities overnight, and woke up to complete, working exploits. Rather than releasing Mythos Preview publicly, Anthropic has launched Project Glasswing. Project Glasswing brings together AWS, Apple, Cisco, CrowdStrike, Google, JPMorgan Chase, the Linux Foundation, Microsoft, NVIDIA, and Palo Alto Networks. Anthropic is committing $100M in usage credits. These organizations will use Mythos Preview to identify and patch vulnerabilities in critical software. Commentary has been swift. On Hacker News someone raised practical concerns around the scale of problem this can uncover: …hundreds of millions of embedded devices that cannot be upgraded easily and will be running vulnerable binaries essentially forever. This was a problem before of course, but the ease of chaining vulnerabilities takes the issue to a new level. A post on x shared benchmarks and captioned with: Claude Mythos just obliterated every single benchmark in AI , with the SWE-bench verified coming in at 93.9%, compared with Claude Opus 4.6 at 80.8%. Discussion on r/BetterOffline took a more skeptical view, arguing that the benchmarks alone aren’t a good measure: Only verifiable capability we saw was its ability to find and exploit long existing vulnerabilities in existing libraries. I would say it's a big deal, even if it's expensive to run. But I bet there are more reasons to not make it public besides "it's too scary". For example might both be not good enough in other avenues and extremely expensive. This model might actually be useful for finding vulnerabilities, but besides that we just don't know if it's good/cost effective on anything else. Benchmarks themselves aren't good enough measure. A thread on reddit asked whether the discussion around Mythos was hype or more marketing, with commenters referencing previous model releases such as GPT2, that had been announced but withheld due to concerns around safety. While Mythos Preview will not be publicly released, Anthropic states findings will inform future Claude releases. The system card and risk report are both available for review. Anthropic is an AI safety company founded by former OpenAI research executives. Its Claude family of models emphasises safety and alignment, using Constitutional AI techniques designed to make models helpful, harmless, and honest. The restricted release of Mythos Preview represents a notable departure from the competitive race-to-release dynamics that have characterised the AI industry in recent years. About the Author Daniel Curtis Show more Show less Rate this Article Adoption Style Author Contacted This content is in the AI, ML & Data Engineering topic Related Topics: AI, ML & Data Engineering Claude Artificial Intelligence Application Security Anthropic AI Coding Security Vulnerabilities Related Editorial Related Sponsors Popular across InfoQ OpenAI Introduces Websocket-Based Execution Mode to Reduce Latency in Agentic Workflows Cangjie, a New Open-Source Compiled Language with Native Effect Handlers and Algebraic Data Types How GitHub Is Securing Agentic Workflows in Modern CI CD Systems Google Announces GKE Agent Sandbox and Hypercluster at Next '26, Positioning Kubernetes as AI Agent Engineering at AI Speed: Lessons from the First Agentically Accelerated Software Project From Java EE to Quarkus and LLMs: Adam Bien’s Playbook for Boring, Future‑Proof Systems The InfoQ Newsletter A round-up of last week’s content on InfoQ sent out every Tuesday. 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