How severe is CVE-2026-25667?

CVE-2026-25667 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-2026-25667 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-25667?

CVE-2026-25667 affects Microsoft .net. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-25667?

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-2026-25667 have an EU (EUVD) identifier?

Yes. CVE-2026-25667 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13148.

When was CVE-2026-25667 published?

CVE-2026-25667 was published on 2026-03-19 and last updated on 2026-06-17.

CVE-2026-25667

CVE-2026-25667 is a high-severity vulnerability in Microsoft .net 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: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13148
Weakness: CWE-400
Affected product: Microsoft .net
Published: 2026-03-19
Last modified: 2026-06-17

Description

ASP.NET Core Kestrel in Microsoft .NET 8.0 before 8.0.22 and .NET 9.0 before 9.0.11 allows a remote attacker to cause excessive CPU consumption by sending a crafted QUIC packet, because of an incorrect exit condition for HTTP/3 Encoder/Decoder stream processing.

Frequently asked questions

What is CVE-2026-25667?: ASP.NET Core Kestrel in Microsoft .NET 8.0 before 8.0.22 and .NET 9.0 before 9.0.11 allows a remote attacker to cause excessive CPU consumption by sending a crafted QUIC packet, because of an incorrect exit condition for HTTP/3 Encoder/Decoder stream processing.
How severe is CVE-2026-25667?: CVE-2026-25667 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-2026-25667 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-25667?: CVE-2026-25667 affects Microsoft .net. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-25667?: 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-2026-25667 have an EU (EUVD) identifier?: Yes. CVE-2026-25667 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13148.
When was CVE-2026-25667 published?: CVE-2026-25667 was published on 2026-03-19 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*

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