How severe is CVE-2012-4776?

CVE-2012-4776 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2012-4776 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-4776?

CVE-2012-4776 primarily affects Microsoft .net Framework. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-4776?

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-2012-4776 published?

CVE-2012-4776 was published on 2012-11-14 and last updated on 2026-06-16.

CVE-2012-4776

CVE-2012-4776 is a critical-severity vulnerability in Microsoft .net Framework with a CVSS 2.0 base score of 9.3. Its EPSS exploit-prediction score of 25% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 2.0 base score 9.3)
EPSS exploit prediction: 25% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft .net Framework
Published: 2012-11-14
Last modified: 2026-06-16

Description

The Web Proxy Auto-Discovery (WPAD) functionality in Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, and 4.5 does not validate configuration data that is returned during acquisition of proxy settings, which allows remote attackers to execute arbitrary JavaScript code by providing crafted data during execution of (1) an XAML browser application (aka XBAP) or (2) a .NET Framework application, aka "Web Proxy Auto-Discovery Vulnerability."

Frequently asked questions

What is CVE-2012-4776?: The Web Proxy Auto-Discovery (WPAD) functionality in Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, and 4.5 does not validate configuration data that is returned during acquisition of proxy settings, which allows remote attackers to execute arbitrary JavaScript code by providing crafted data during execution of (1) an XAML browser application (aka XBAP) or (2) a .NET Framework application, aka "Web Proxy Auto-Discovery Vulnerability."
How severe is CVE-2012-4776?: CVE-2012-4776 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2012-4776 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-4776?: CVE-2012-4776 primarily affects Microsoft .net Framework. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-4776?: 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-2012-4776 published?: CVE-2012-4776 was published on 2012-11-14 and last updated on 2026-06-16.

References

Affected products (5)

cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.5:*:*:*:*:*:*:*

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