How severe is CVE-2011-1243?

CVE-2011-1243 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2011-1243 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 29% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-1243?

CVE-2011-1243 primarily affects Microsoft Windows Xp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-1243?

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-2011-1243 published?

CVE-2011-1243 was published on 2011-04-13 and last updated on 2026-06-16.

CVE-2011-1243

CVE-2011-1243 is a critical-severity vulnerability in Microsoft Windows Xp with a CVSS 2.0 base score of 9.3. Its EPSS exploit-prediction score of 29% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-119.

Key facts

Severity: Critical (CVSS 2.0 base score 9.3)
EPSS exploit prediction: 29% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Microsoft Windows Xp
Published: 2011-04-13
Last modified: 2026-06-16

Description

The Windows Messenger ActiveX control in msgsc.dll in Microsoft Windows XP SP2 and SP3 allows remote attackers to execute arbitrary code via unspecified vectors that "corrupt the system state," aka "Microsoft Windows Messenger ActiveX Control Vulnerability."

Frequently asked questions

What is CVE-2011-1243?: The Windows Messenger ActiveX control in msgsc.dll in Microsoft Windows XP SP2 and SP3 allows remote attackers to execute arbitrary code via unspecified vectors that "corrupt the system state," aka "Microsoft Windows Messenger ActiveX Control Vulnerability."
How severe is CVE-2011-1243?: CVE-2011-1243 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2011-1243 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 29% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-1243?: CVE-2011-1243 primarily affects Microsoft Windows Xp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-1243?: 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-2011-1243 published?: CVE-2011-1243 was published on 2011-04-13 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:*

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