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:*:*:*:*:*

More vulnerabilities in Microsoft Windows Xp

CVE-2013-3195 — Critical (CVSS 10.0): The DSA_InsertItem function in Comctl32.dll in the Windows common control library in Microsoft Windows XP SP2, Windows…
CVE-2013-3175 — Critical (CVSS 10.0): Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1,…
CVE-2012-4786 — Critical (CVSS 10.0): The kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server…
CVE-2012-1853 — Critical (CVSS 10.0): Stack-based buffer overflow in the Remote Administration Protocol (RAP) implementation in the LanmanWorkstation service…
CVE-2012-1852 — Critical (CVSS 10.0): Heap-based buffer overflow in the Remote Administration Protocol (RAP) implementation in the LanmanWorkstation service…
CVE-2012-1851 — Critical (CVSS 10.0): Format string vulnerability in the Print Spooler service in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2,…

All CVEs affecting Microsoft Windows Xp →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →