CVE-2018-8421
CVE-2018-8421 is a critical-severity vulnerability in Microsoft .net Framework with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 29% 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 3.x base score 9.8)
- CVSS v2: 10.0
- EPSS exploit prediction: 29% (98th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-20
- Affected product: Microsoft .net Framework
- Published:
- Last modified:
Description
A remote code execution vulnerability exists when Microsoft .NET Framework processes untrusted input, aka ".NET Framework Remote Code Execution Vulnerability." This affects Microsoft .NET Framework 4.6, Microsoft .NET Framework 3.5, Microsoft .NET Framework 4.7/4.7.1/4.7.2, Microsoft .NET Framework 3.0, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.1/4.7.2, Microsoft .NET Framework 4.7.1/4.7.2, Microsoft .NET Framework 4.7.2, Microsoft .NET Framework 2.0.
Frequently asked questions
- What is CVE-2018-8421?
- A remote code execution vulnerability exists when Microsoft .NET Framework processes untrusted input, aka ".NET Framework Remote Code Execution Vulnerability." This affects Microsoft .NET Framework 4.6, Microsoft .NET Framework 3.5, Microsoft .NET Framework 4.7/4.7.1/4.7.2, Microsoft .NET Framework 3.0, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.1/4.7.2, Microsoft .NET Framework 4.7.1/4.7.2, Microsoft .NET Framework 4.7.2, Microsoft .NET Framework 2.0.
- How severe is CVE-2018-8421?
- CVE-2018-8421 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-2018-8421 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 29% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2018-8421?
- CVE-2018-8421 primarily affects Microsoft .net Framework. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2018-8421?
- 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-2018-8421 published?
- CVE-2018-8421 was published on 2018-09-13 and last updated on 2026-06-17.
References
- http://www.securityfocus.com/bid/105222
- http://www.securitytracker.com/id/1041636
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8421
Affected products (11)
- cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:3.0:sp2:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:3.5:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.5.2:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.6:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:.net_framework:4.6.1:*:*:*:*:*:*:*
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