Kernel crash via unrestricted MSR write IOCTL
Published Sep 4, 2026 · Updated Sep 4, 2026
DirectIo64.sys in PassMark PerformanceTest, BurnInTest, and OSForensics allows local users to read MSRs or crash the Windows kernel. Its read IOCTL rejects only two MSRs, while its zero-write IOCTL applies no blocklist and accepts any caller-supplied MSR index. A low-privileged process must reach a loaded, non-exclusively held driver; reading IA32_GS_BASE exposes a kernel pointer, while zeroing IA32_LSTAR causes an unrecoverable crash on the next system call.
Summary
What happened
DirectIo64.sys in PassMark PerformanceTest, BurnInTest, and OSForensics allows local users to read MSRs or crash the Windows kernel. Its read IOCTL rejects only two MSRs, while its zero-write IOCTL applies no blocklist and accepts any caller-supplied MSR index. A low-privileged process must reach a loaded, non-exclusively held driver; reading IA32_GS_BASE exposes a kernel pointer, while zeroing IA32_LSTAR causes an unrecoverable crash on the next system call.
The record
- CVE
- CVE-2026-80115
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- PassMark Software
- Product
- BurnInTest
- Classifications
- CWE-782, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <11.1 build 1000
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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