How severe is CVE-2011-0657?

CVE-2011-0657 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-2011-0657 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 63% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-0657?

CVE-2011-0657 primarily affects Microsoft Windows 2003 Server. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-0657?

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-2011-0657 published?

CVE-2011-0657 was published on 2011-04-13 and last updated on 2026-06-16.

CVE-2011-0657

CVE-2011-0657 is a critical-severity vulnerability in Microsoft Windows 2003 Server with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 63% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 63% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft Windows 2003 Server
Published: 2011-04-13
Last modified: 2026-06-16

Description

DNSAPI.dll in the DNS client in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 does not properly process DNS queries, which allows remote attackers to execute arbitrary code via (1) a crafted LLMNR broadcast query or (2) a crafted application, aka "DNS Query Vulnerability."

Frequently asked questions

What is CVE-2011-0657?: DNSAPI.dll in the DNS client in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 does not properly process DNS queries, which allows remote attackers to execute arbitrary code via (1) a crafted LLMNR broadcast query or (2) a crafted application, aka "DNS Query Vulnerability."
How severe is CVE-2011-0657?: CVE-2011-0657 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-2011-0657 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 63% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-0657?: CVE-2011-0657 primarily affects Microsoft Windows 2003 Server. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-0657?: 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-2011-0657 published?: CVE-2011-0657 was published on 2011-04-13 and last updated on 2026-06-16.

References

Affected products (18)

cpe:2.3:o:microsoft:windows_2003_server:*:sp2:*:*:*:*:*:*
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_2003:*:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:itanium:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:x32:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:*:x64:*:*:*:*:*
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:*:sp1:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_vista:*:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:*:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:*

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