CVE-2011-2013Windows 7 Integer Overflow
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…
Published Nov 8, 2011 · Updated Apr 28, 2026
Key Facts
Patch immediately- CVE-2011-2013 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Windows 7 (Microsoft), Windows Server 2008 (Microsoft), Windows Vista (Microsoft).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 32% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
32%
Higher than 98.3% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
37/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
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."
Affected Products
9 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 7Microsoft | See advisory | n/a |
| Windows Server 2008Microsoft | r2 | n/a |
| Windows VistaMicrosoft | See advisory | n/a |
Timeline
Publicly disclosed
Nov 8, 2011
Last updated
Apr 28, 2026
Weakness Type
- CWE-189
- CWE-190 Integer Overflow or Wraparound
References
- exploitExploitDB-36285
- otherMS11-083
- otheroval:org.mitre.oval:def:13877
- other1026290
FAQ
Common Questions.
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."
Affected: Windows 7 (Microsoft); Windows Server 2008 (Microsoft) versions r2; Windows Vista (Microsoft). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2011-2013 On Your Attack Surface?
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