CVE Intelligence
CISA KEV High Denial of service

CVE-2023-38180 — Microsoft .NET Core and Visual Studio Denial-of-Service Vulnerability

.NET and Visual Studio Denial of Service Vulnerability

Published Aug 8, 2023 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: microsoft

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Aug 9, 2023
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • EPSS 14% (30-day exploitation probability)+14
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Aug 9, 2023
EPSS FIRST
14.02%
ahead of 97% of scored CVEs · Oct 14, 2026
Affects
Fedoraproject
Fedora and 14 more
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — msrc.microsoft.com (NIST National Vulnerability Database)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-arm64: fixed in version 7.0.10 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-arm64: fixed in version 6.0.21 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-x64: fixed in version 7.0.10 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-x64: fixed in version 6.0.21 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-x86: fixed in version 7.0.10 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.App.Runtime.win-x86: fixed in version 6.0.21 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv: fixed in version 6.0.21 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv: fixed in version 2.1.40 — github.com (GitHub Security Advisories)
  • Nuget Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets: fixed in version 2.1.40 — github.com (GitHub Security Advisories)

CISA required action CISA

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

US federal deadline: Aug 30, 2023 — passed 1142 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Fedoraproject Fedora, Microsoft .net, Microsoft .NET 6.0…).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  4. Apply the fixed version or the patch documented under Remediation.
  5. EPSS ahead of 97% of scored CVEs: prioritize it in the patch queue.
  6. Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Fedoraproject Fedora version 38version 37 Vulnerable NIST National Vulnerability Database
Microsoft .net ≥ 6.0.0 and < 6.0.21≥ 7.0.0 and < 7.0.10 Vulnerable NIST National Vulnerability Database
Microsoft .NET 6.0 ≥ 6.0.0 and < 6.0.21 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft .NET 7.0 ≥ 7.0.0 and < 7.0.10 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft Asp.net Core ≥ 2.1 and < 2.1.40 Vulnerable NIST National Vulnerability Database
Microsoft ASP.NET Core 2.1 ≥ 2.0 and < 2.1.40 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft Microsoft Visual Studio 2022 version 17.2 ≥ 17.2.0 and < 17.2.18 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft Microsoft Visual Studio 2022 version 17.4 ≥ 17.4.0 and < 17.4.10 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft Microsoft Visual Studio 2022 version 17.6 ≥ 17.6.0 and < 17.6.6 Vulnerable CVE Program (cve.org) e CISA ADP
Microsoft Visual Studio 2022 ≥ 17.6.0 and < 17.6.6≥ 17.4.0 and < 17.4.10≥ 17.2.0 and < 17.2.18 Vulnerable NIST National Vulnerability Database
Nuget Microsoft.AspNetCore.App.Runtime.win-arm64 ≥ 7.0.0 and ≤ 7.0.9≥ 6.0.0 and ≤ 6.0.20 Vulnerable GitHub Security Advisories
Nuget Microsoft.AspNetCore.App.Runtime.win-x64 ≥ 7.0.0 and ≤ 7.0.9≥ 6.0.0 and ≤ 6.0.20 Vulnerable GitHub Security Advisories
Nuget Microsoft.AspNetCore.App.Runtime.win-x86 ≥ 7.0.0 and ≤ 7.0.9≥ 6.0.0 and ≤ 6.0.20 Vulnerable GitHub Security Advisories
Nuget Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv ≥ 6.0.0 and ≤ 6.0.20≤ 2.1.39 Vulnerable GitHub Security Advisories
Nuget Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets ≤ 2.1.39 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 secure@microsoft.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.1 High — — microsoft via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: secure@microsoft.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-400 · Uncontrolled Resource Consumption

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Aug 9, 2023
Federal deadline
Aug 30, 2023
passed 1142 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 14.02%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Track CPU/memory spikes and availability drops correlated with request patterns.
  • Hunt retroactively in logs from before Aug 9, 2023 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPSresource metrics

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · nuget/microsoft.aspnetcore.app.runtime.win-arm64, nuget/microsoft.aspnetcore.app.runtime.win-x64, nuget/microsoft.aspnet
    Oct 13, 2026 · GitHub Security Advisories
  • Affected products added · microsoft/.net 6.0, microsoft/.net 7.0, microsoft/asp.net core 2.1, microsoft/microsoft visual studio 2022 version 17.2,
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • Affected products added · microsoft/.net, microsoft/asp.net core, microsoft/visual studio 2022, fedoraproject/fedora
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2023
  • Added to CISA KEV catalog
    Aug 8, 2023 · CISA
  • CVE published
    Aug 8, 2023 · microsoft

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

10 on the record

Elsewhere on this site

Fedoraproject
every CVE for this vendor
2023-08
what else CISA listed that month
Denial of service
same class
CWE-400
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-96236 ASP.NET Core Denial of Service Vulnerability 2d
  • CVE-2026-88092 ASP.NET Core Tampering Vulnerability 2d
  • CVE-2026-70188 ASP.NET Core Security Feature Bypass Vulnerability 2d
  • CVE-2026-70196 ASP.NET Core Denial of Service Vulnerability 2d
  • CVE-2026-70186 ASP.NET Core Denial of Service Vulnerability 2d
  • CVE-2026-70183 ASP.NET Core Elevation of Privilege Vulnerability 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-38180 is "Microsoft .NET Core and Visual Studio Denial-of-Service Vulnerability", rated High. It affects Fedora (Fedoraproject); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.5 describes technical severity. EPSS 14.02% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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