How severe is CVE-2011-1978?

CVE-2011-1978 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2011-1978 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-1978?

CVE-2011-1978 primarily affects Microsoft .net Framework. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-1978?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2011-1978 published?

CVE-2011-1978 was published on 2011-08-10 and last updated on 2026-06-16.

CVE-2011-1978

CVE-2011-1978 is a medium-severity vulnerability in Microsoft .net Framework with a CVSS 2.0 base score of 4.3. Its EPSS exploit-prediction score of 20% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Microsoft .net Framework
Published: 2011-08-10
Last modified: 2026-06-16

Description

Microsoft .NET Framework 2.0 SP2, 3.5.1, and 4 does not properly validate the System.Net.Sockets trust level, which allows remote attackers to obtain sensitive information or trigger arbitrary outbound network traffic via (1) a crafted XAML browser application (aka XBAP), (2) a crafted ASP.NET application, or (3) a crafted .NET Framework application, aka "Socket Restriction Bypass Vulnerability."

Frequently asked questions

What is CVE-2011-1978?: Microsoft .NET Framework 2.0 SP2, 3.5.1, and 4 does not properly validate the System.Net.Sockets trust level, which allows remote attackers to obtain sensitive information or trigger arbitrary outbound network traffic via (1) a crafted XAML browser application (aka XBAP), (2) a crafted ASP.NET application, or (3) a crafted .NET Framework application, aka "Socket Restriction Bypass Vulnerability."
How severe is CVE-2011-1978?: CVE-2011-1978 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2011-1978 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-1978?: CVE-2011-1978 primarily affects Microsoft .net Framework. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-1978?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-1978 published?: CVE-2011-1978 was published on 2011-08-10 and last updated on 2026-06-16.

References

Affected products (3)

cpe:2.3:a:microsoft:.net_framework:4.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:*

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