Microsoft MDASH Found 4 Critical Windows RCEs — Project Perception Brings Multi-Model Security Routing to Enterprises

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Microsoft’s agentic security system MDASH (Multi-Model Agentic Scanning Harness) found 16 real Windows vulnerabilities — 4 of them critical remote code execution flaws — patched in the April 2026 Patch Tuesday release (April 14). Microsoft’s own disclosure lines for the two example CVEs both read “patched in April Patch Tuesday,” which matches independent vulnerability trackers (CrowdStrike’s April 2026 Patch Tuesday analysis, Zero Day Initiative’s write-up of CVE-2026-33824) — Microsoft’s May 12 blog post announcing MDASH publicly came a month after the actual patch date. Now MDASH is entering private preview as a customer-accessible product, and the commercial standalone version, Project Perception, entered public preview on August 3, 2026 (see update below). The full story is documented in the Microsoft Security Blog’s May 12 announcement.

For builders, this matters in two ways: first, it’s proof that multi-agent, multi-model security tooling works at production quality; second, the routing architecture — expensive reasoning reserved for deep analysis, cheap models handling bulk triage — is a pattern every builder doing AI at scale should understand.

Part of our Builder’s Log.

What MDASH Found

MDASH’s first public result was 16 CVEs patched in the April 2026 Patch Tuesday, including 4 Critical RCE vulnerabilities. Ten of the 16 are kernel-mode flaws, six are user-mode. Most are reachable from a network position without credentials — meaning attackers could exploit them remotely without authentication (SiliconAngle).

Two of the four critical flaws illustrate the kind of finding MDASH is designed to surface:

CVE-2026-33824 (IKEv2): A double-free in ikeext.dll, the Windows IKEv2 service, reachable by a remote unauthenticated attacker over UDP/500. By sending a crafted IKE_SA_INIT carrying Microsoft’s IPsec Security Realm Id vendor-ID payload, followed by a single IKEv2 fragment that reassembles immediately, an attacker can trigger a deterministic double-free of a 16-byte heap allocation inside the IKEEXT service, which runs as LocalSystem inside svchost.exe — a pre-authentication RCE path into one of the highest-privilege contexts on the system. These specifics come directly from Microsoft’s own technical writeup; The Hacker News covered it as one of the most serious findings in the batch, and Zero Day Initiative’s independent analysis rates it CVSS 9.8.

CVE-2026-33827 (TCP/IP): A remote unauthenticated use-after-free in tcpip.sys triggered by crafted IPv4 packets carrying the Strict Source and Record Route (SSRR) option, per Microsoft’s writeup and SiliconAngle’s coverage — a reference-counted Path object whose ownership was dropped before a later reuse, with three independent concurrent free paths in play. Third-party vulnerability trackers classify the root cause as CWE-362 (race condition), consistent with a use-after-free triggered by unsynchronized concurrent frees.

The full batch spans tcpip.sys (8 CVEs, the most-affected component), the IKEEXT IPsec service (2 CVEs), HTTP.sys, Netlogon, DNS resolution (dnsapi.dll), and the Telnet client — a meaningful cross-section of Windows networking and authentication components, per Microsoft’s own vulnerability table.

How MDASH Works: 100+ Agents, a Multi-Model Router

MDASH was built by Microsoft’s Autonomous Code Security (ACS) team in collaboration with Microsoft Offensive Research & Security Engineering (MORSE) and the Windows Attack Research and Protection (WARP) group, per Microsoft’s own announcement. The architecture coordinates more than 100 specialized AI agents, using a mix of heavyweight frontier models and lightweight distilled models (Microsoft Security Blog).

The key mechanism is the model router: an orchestration layer that assigns tasks based on complexity and cost.

• Cheap models handle initial triage, log parsing, inventory checks, and deduplication of common vulnerability patterns.
• Frontier models handle deep exploitability analysis — reasoning through complex exploit chains, modeling attacker-reachability, and producing evidence-backed reports.

Microsoft’s MDASH blog post doesn’t name which vendors’ models sit in its router, describing them only as “frontier and distilled models.” The Microsoft, OpenAI, and Anthropic mix is specifically reported for the commercial Project Perception router, per WindowsNews and WindowsNews’s separate MDASH private-preview coverage. As WindowsNews reported on the Project Perception architecture: “A low-cost model might handle inventory checks, log parsing, or initial triage of common vulnerability types. When the system needs to reason through a complex exploit chain, interpret an authentication flow, or write a remediation plan that touches production systems, it calls on a frontier model.”

MDASH integrates with existing security workflows: scanning via the Defender CLI or GitHub connectors, with findings reviewed in the Microsoft Defender portal before human security engineers decide on action. No autonomous patching. Human validation is mandatory for all findings — WindowsNews reports Microsoft describes the scan-triage-fix-validate-deploy loop as “a human-driven process with AI as a high-speed assistant,” not an autonomous patch-bot.

From MDASH to Project Perception

MDASH and Project Perception are distinct products with a clear relationship, as WindowsNews detailed in its MDASH private preview coverage:

Update, August 8, 2026: Project Perception actually entered public preview on August 3, 2026 — a few days after the original “by end of July” expectation cited above. Per Microsoft’s own Project Perception page, the system is “an agentic system that brings a workforce of specialized AI agents to reason over your security data, tools, and workflows,” organized into red/blue/green agent teams plus a purpose-built model called MAI-Cyber-1, and it “can assess risk across identities, endpoints, applications, data, cloud environments, and AI systems.” At launch it plugs directly into Microsoft Defender, with broader Microsoft Security product coverage promised “over time.” TechRepublic reports Microsoft has not yet disclosed simple public pricing, detailed eligibility requirements, or a general-availability date.

Pricing is consumption-based: Microsoft’s official page states customers “pay only for what you use, measured in Security Compute Units (SCUs),” with different agents consuming SCUs at different rates. It is expected to be sold as a separate SKU outside existing bundles like Microsoft 365 E5.

The Cost Angle vs. Anthropic Mythos

Anthropic’s Claude Mythos, announced April 7, 2026 as part of Project Glasswing, was a landmark early example of a frontier model autonomously finding and exploiting software vulnerabilities at scale — Anthropic reported it found “thousands of high-severity vulnerabilities, including some in every major operating system and web browser.” Wiz’s analysis frames it as “the continuation of a trend” in AI-driven vulnerability research rather than the creation of an entirely new category. Mythos 5 is priced at $10 per million input tokens and $50 per million output tokens, per Anthropic’s own Mythos page — exactly double Claude Opus 4.8’s standard $5/$25 pricing, and roughly double on input / 67% higher on output versus OpenAI’s GPT-5.6 Sol at $5/$30. Mythos 5 is a limited-availability, restricted-access model (it lacks the safety classifiers of its generally-available sibling, Claude Fable 5, which shares the same $10/$50 pricing) — not something any customer can currently buy off the shelf.

Project Perception’s cost advantage is structural, not a discount: it reserves frontier-model reasoning only for the analysis steps that actually require it, while cheap models absorb the high-volume bulk work. If 80% of a scan’s token budget goes to triage that a $0.30/M input model can handle, the effective per-vulnerability cost drops substantially even if the per-token rate for the frontier tier is equivalent.

Microsoft’s additional advantage is deep integration with Windows Update, GitHub, Azure, and the Defender ecosystem — surface area that reduces the data ingestion and tooling overhead a Mythos deployment would require a customer to build from scratch.

Builder Implications

Three patterns worth noting for builders doing multi-model or security-adjacent work:

1. The routing pattern is proven at production scale. MDASH found 4 critical kernel-level RCE flaws using a tiered routing strategy. For builders designing multi-model pipelines, the pattern is now validated: reserve expensive reasoning capacity for the tasks where it demonstrably matters; route everything else to cost-efficient inference.

2. Human-in-the-loop on remediation is the responsible design. MDASH and Project Perception both require human review before any fix is applied. This is the pattern the industry is converging on for high-stakes agentic outputs — not because the models aren’t capable, but because the blast radius of an autonomous security patch on a kernel component is unacceptable. Builders designing agentic workflows in sensitive domains (code changes, infrastructure mutations, financial transactions) should expect this pattern to become the default.

3. Breadth of scan surface matters more than depth alone. Mythos excels at deep reasoning over a bounded scope. Project Perception, per Microsoft’s own description, is built to “assess risk across identities, endpoints, applications, data, cloud environments, and AI systems” using coordinated red/blue/green agent teams. For enterprise buyers, that breadth of coverage is a real procurement factor against a point solution scoped to code.

What We Don’t Know Yet

As originally published, July 18, 2026: Microsoft had not announced Project Perception’s launch date beyond “as early as this month,” and no pricing or enterprise licensing tiers had been confirmed. The private preview of MDASH remained select-customers-only, with no public waitlist announced. No benchmark comparison between Project Perception and Mythos on a standardized vulnerability set had been published.

As of the August 8, 2026 audit: Project Perception has since entered public preview (August 3, 2026) with a disclosed SCU-based pricing model, but per TechRepublic, Microsoft still has not published simple public pricing, detailed eligibility requirements, or a general-availability date. No standardized benchmark comparison between Project Perception and Mythos has been published.

When Project Perception reaches general availability, the metrics to watch: time-to-triage per CVE, false-positive rate on bulk scanning, and cost-per-confirmed-critical finding vs. Mythos on the same codebase.

Sources: Microsoft Security Blog, May 12 2026; SiliconAngle, May 13 2026; The Hacker News, May 2026; Zero Day Initiative on CVE-2026-33824; CrowdStrike, April 2026 Patch Tuesday analysis; WindowsNews on Project Perception; WindowsNews on MDASH private preview; NewsBytesApp on launch timeline; Microsoft’s official Project Perception page; TechRepublic on public preview; Anthropic on Claude Mythos; Anthropic’s Project Glasswing announcement; Wiz on Claude Mythos; Anthropic on Claude Opus 4.8 pricing; OpenAI on GPT-5.6