How severe is CVE-2012-4777?

CVE-2012-4777 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2012-4777 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-2012-4777?

CVE-2012-4777 primarily affects Microsoft .net Framework. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-4777?

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-2012-4777 published?

CVE-2012-4777 was published on 2012-11-14 and last updated on 2026-06-16.

CVE-2012-4777

CVE-2012-4777 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-264.

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-264
Affected product: Microsoft .net Framework
Published: 2012-11-14
Last modified: 2026-06-16

Description

The code-optimization feature in the reflection implementation in Microsoft .NET Framework 4 and 4.5 does not properly enforce object permissions, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP) or (2) a crafted .NET Framework application, aka "WPF Reflection Optimization Vulnerability."

Frequently asked questions

What is CVE-2012-4777?: The code-optimization feature in the reflection implementation in Microsoft .NET Framework 4 and 4.5 does not properly enforce object permissions, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP) or (2) a crafted .NET Framework application, aka "WPF Reflection Optimization Vulnerability."
How severe is CVE-2012-4777?: CVE-2012-4777 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2012-4777 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-2012-4777?: CVE-2012-4777 primarily affects Microsoft .net Framework. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-4777?: 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-2012-4777 published?: CVE-2012-4777 was published on 2012-11-14 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:a:microsoft:.net_framework:4.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.5:*:*:*:*:*:*:*

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