How severe is CVE-2011-2013?

CVE-2011-2013 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2011-2013 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 34% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2013?

CVE-2011-2013 primarily affects Microsoft Windows 7. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2013?

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-2011-2013 published?

CVE-2011-2013 was published on 2011-11-08 and last updated on 2026-06-16.

CVE-2011-2013

CVE-2011-2013 is a critical-severity vulnerability in Microsoft Windows 7 with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 34% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-189.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 34% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-189
Affected product: Microsoft Windows 7
Published: 2011-11-08
Last modified: 2026-06-16

Description

Integer overflow in the TCP/IP implementation in Microsoft Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code by sending a sequence of crafted UDP packets to a closed port, aka "Reference Counter Overflow Vulnerability."

Frequently asked questions

What is CVE-2011-2013?: Integer overflow in the TCP/IP implementation in Microsoft Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code by sending a sequence of crafted UDP packets to a closed port, aka "Reference Counter Overflow Vulnerability."
How severe is CVE-2011-2013?: CVE-2011-2013 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2011-2013 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 34% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2013?: CVE-2011-2013 primarily affects Microsoft Windows 7. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2013?: 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-2011-2013 published?: CVE-2011-2013 was published on 2011-11-08 and last updated on 2026-06-16.

References

Affected products (9)

cpe:2.3:o:microsoft:windows_7:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_7:-:sp1:x64:*:*:*:*:*
cpe:2.3:o:microsoft:windows_7:-:sp1:x86:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x32:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x64:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:itanium:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:r2:*:itanium:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:r2:*:x64:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:*:sp2:*:*:*:*:*:*

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