How severe is CVE-2026-45591?

CVE-2026-45591 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-2026-45591 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-45591?

CVE-2026-45591 primarily affects Microsoft Asp.net Core. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-45591?

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.

Does CVE-2026-45591 have an EU (EUVD) identifier?

Yes. CVE-2026-45591 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35549.

When was CVE-2026-45591 published?

CVE-2026-45591 was published on 2026-06-09 and last updated on 2026-06-30.

CVE-2026-45591

CVE-2026-45591 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. The underlying weakness is classified as CWE-400.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35549
Weakness: CWE-400
Affected product: Microsoft Asp.net Core
Published: 2026-06-09
Last modified: 2026-06-30

Description

Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Frequently asked questions

What is CVE-2026-45591?: Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.
How severe is CVE-2026-45591?: CVE-2026-45591 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-2026-45591 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-45591?: CVE-2026-45591 primarily affects Microsoft Asp.net Core. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-45591?: 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.
Does CVE-2026-45591 have an EU (EUVD) identifier?: Yes. CVE-2026-45591 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35549.
When was CVE-2026-45591 published?: CVE-2026-45591 was published on 2026-06-09 and last updated on 2026-06-30.

References

Affected products (3)

cpe:2.3:a:microsoft:asp.net_core:*:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2026:*:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*

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