How severe is CVE-2009-1542?

CVE-2009-1542 has a CVSS 2.0 base score of 9.0, rated critical severity.

Is CVE-2009-1542 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-1542?

CVE-2009-1542 primarily affects Microsoft Virtual Pc. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-1542?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2009-1542 published?

CVE-2009-1542 was published on 2009-07-15 and last updated on 2026-06-16.

CVE-2009-1542

CVE-2009-1542 is a critical-severity vulnerability in Microsoft Virtual Pc with a CVSS 2.0 base score of 9.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-264.

Key facts

Severity: Critical (CVSS 2.0 base score 9.0)
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Microsoft Virtual Pc
Published: 2009-07-15
Last modified: 2026-06-16

Description

The Virtual Machine Monitor (VMM) in Microsoft Virtual PC 2004 SP1, 2007, and 2007 SP1, and Microsoft Virtual Server 2005 R2 SP1, does not enforce CPU privilege-level requirements for all machine instructions, which allows guest OS users to execute arbitrary kernel-mode code and gain privileges within the guest OS via a crafted application, aka "Virtual PC and Virtual Server Privileged Instruction Decoding Vulnerability."

Frequently asked questions

What is CVE-2009-1542?: The Virtual Machine Monitor (VMM) in Microsoft Virtual PC 2004 SP1, 2007, and 2007 SP1, and Microsoft Virtual Server 2005 R2 SP1, does not enforce CPU privilege-level requirements for all machine instructions, which allows guest OS users to execute arbitrary kernel-mode code and gain privileges within the guest OS via a crafted application, aka "Virtual PC and Virtual Server Privileged Instruction Decoding Vulnerability."
How severe is CVE-2009-1542?: CVE-2009-1542 has a CVSS 2.0 base score of 9.0, rated critical severity.
Is CVE-2009-1542 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-1542?: CVE-2009-1542 primarily affects Microsoft Virtual Pc. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-1542?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2009-1542 published?: CVE-2009-1542 was published on 2009-07-15 and last updated on 2026-06-16.

References

Affected products (6)

cpe:2.3:a:microsoft:virtual_pc:2004:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:virtual_pc:2007:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:virtual_pc:2007:*:x64:*:*:*:*:*
cpe:2.3:a:microsoft:virtual_pc:2007:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:virtual_server:2005:r2_sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:virtual_server:2005:r2_sp1:x64:*:*:*:*:*

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