CVE-2025-21333 — AI Deep Analysis Summary

Q: Root Cause? (CWE/Flaw)

🛑 **CWE-122**: Heap-Based Buffer Overflow. 🔍 **Flaw**: Improper bounds checking when handling specific I/O ring entries (`IOP_MC_BUFFER_ENTRY`) and WNF state data within the Hyper-V virtualization stack.

Q: Who is affected? (Versions/Components)

🖥️ **Affected Systems**: • Windows 10 Version 21H2 (x64) • Windows 11 Version 22H2 (ARM64 & x64) 📦 **Component**: Hyper-V NT Kernel Integration VSP (`vkrnlintvsp.sys`).

Q: Is exploitation threshold high? (Auth/Config)

⚠️ **Threshold**: **Low**. 🔑 **Auth Required**: Yes, requires **Local Privileges** (PR:L). 🖱️ **User Interaction**: None required (UI:N). 🌐 **Attack Vector**: Local (AV:L).

Q: Is it urgent? (Priority Suggestion)

🚨 **Priority: CRITICAL**. ⏱️ **Urgency**: **Immediate Action Required**. 💡 **Reason**: Active exploitation in the wild + High Impact (System Takeover) + Low Barrier to Entry (Local Auth). Patch now!

Updated May 06, 2026 CVSS 7.8 · High

This is a summary of the AI-generated 10-question deep analysis. The full version (longer answers, follow-up Q&A, related CVEs) requires login. Read the full analysis →

Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: A critical **Heap-Based Buffer Overflow** in Microsoft Hyper-V's `vkrnlintvsp.sys`.…

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Q2Root Cause? (CWE/Flaw)

🛑 **CWE-122**: Heap-Based Buffer Overflow. <br>🔍 **Flaw**: Improper bounds checking when handling specific I/O ring entries (`IOP_MC_BUFFER_ENTRY`) and WNF state data within the Hyper-V virtualization stack.

Q3Who is affected? (Versions/Components)

🖥️ **Affected Systems**: <br>• Windows 10 Version 21H2 (x64) <br>• Windows 11 Version 22H2 (ARM64 & x64) <br>📦 **Component**: Hyper-V NT Kernel Integration VSP (`vkrnlintvsp.sys`).

Q4What can hackers do? (Privileges/Data)

👑 **Privilege Escalation**: Attackers can elevate privileges from **Low/Local** to **System/Kernel** level. <br>🔓 **Impact**: Full control over the host, data theft, and persistence.…

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Q5Is exploitation threshold high? (Auth/Config)

⚠️ **Threshold**: **Low**. <br>🔑 **Auth Required**: Yes, requires **Local Privileges** (PR:L). <br>🖱️ **User Interaction**: None required (UI:N). <br>🌐 **Attack Vector**: Local (AV:L).

Q6Is there a public Exp? (PoC/Wild Exploitation)

🔥 **Yes, Active Exploitation**. <br>📂 **POCs Available**: Multiple GitHub repos (e.g., MrAle98, Mukesh-blend) provide working exploits. <br>⚠️ **Warning**: Threat actors are **actively exploiting** this in the wild.…

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Q7How to self-check? (Features/Scanning)

🔍 **Detection**: <br>• Monitor for abnormal `vkrnlintvsp.sys` activity. <br>• Use KQL queries (see `aleongx/KQL_sentinel_CVE-2025-21333`) in Microsoft Sentinel.…

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Q8Is it fixed officially? (Patch/Mitigation)

🛡️ **Official Fix**: Yes. <br>📅 **Published**: Jan 14, 2025. <br>🔗 **Source**: Microsoft Security Response Center (MSRC).…

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Q9What if no patch? (Workaround)

🚧 **Mitigation (If No Patch)**: <br>1. **Disable Hyper-V** if not strictly needed (via Windows Features). <br>2.…

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Q10Is it urgent? (Priority Suggestion)

🚨 **Priority: CRITICAL**. <br>⏱️ **Urgency**: **Immediate Action Required**. <br>💡 **Reason**: Active exploitation in the wild + High Impact (System Takeover) + Low Barrier to Entry (Local Auth). Patch now!

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Vulnerability detail Full AI analysis (login) Microsoft CWE-122