How severe is CVE-2021-1723?

CVE-2021-1723 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-2021-1723 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1723?

CVE-2021-1723 primarily affects Microsoft Asp.net Core. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1723?

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-2021-1723 published?

CVE-2021-1723 was published on 2021-01-12 and last updated on 2026-06-17.

CVE-2021-1723

CVE-2021-1723 is a high-severity vulnerability in Microsoft Asp.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.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Asp.net Core
Published: 2021-01-12
Last modified: 2026-06-17

Description

ASP.NET Core and Visual Studio Denial of Service Vulnerability

Frequently asked questions

What is CVE-2021-1723?: ASP.NET Core and Visual Studio Denial of Service Vulnerability
How severe is CVE-2021-1723?: CVE-2021-1723 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-2021-1723 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1723?: CVE-2021-1723 primarily affects Microsoft Asp.net Core. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1723?: 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-2021-1723 published?: CVE-2021-1723 was published on 2021-01-12 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:microsoft:asp.net_core:*:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

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