How severe is CVE-2019-0820?

CVE-2019-0820 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-0820 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-0820?

CVE-2019-0820 primarily affects Microsoft .net Core. In total, 27 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-0820?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-0820 published?

CVE-2019-0820 was published on 2019-05-16 and last updated on 2026-06-17.

CVE-2019-0820

CVE-2019-0820 is a high-severity vulnerability in Microsoft .net Core with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 6% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Microsoft .net Core
Published: 2019-05-16
Last modified: 2026-06-17

Description

A denial of service vulnerability exists when .NET Framework and .NET Core improperly process RegEx strings, aka '.NET Framework and .NET Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0980, CVE-2019-0981.

Frequently asked questions

What is CVE-2019-0820?: A denial of service vulnerability exists when .NET Framework and .NET Core improperly process RegEx strings, aka '.NET Framework and .NET Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0980, CVE-2019-0981.
How severe is CVE-2019-0820?: CVE-2019-0820 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-0820 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-0820?: CVE-2019-0820 primarily affects Microsoft .net Core. In total, 27 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-0820?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-0820 published?: CVE-2019-0820 was published on 2019-05-16 and last updated on 2026-06-17.

References

Affected products (27)

cpe:2.3:a:microsoft:.net_core:1.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_core:1.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_core:2.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_core:2.2:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.1:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.6:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.6:*:*:*:*:*:*:*

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