CVE-2023-38180
CVE-2023-38180 is a security flaw in Microsoft .NET Core and Visual Studio, the framework many Windows apps are built on. Attackers can crash Microsoft .NET Core and Visual Studio or stop it working. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 9 Aug 2023.[1]
Microsoft .NET Core and Visual Studio is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 6.0.21, 7.0.10, 2.1.40 and 17.2.18 and others.
Description
CISA calls it a denial-of-service in Microsoft .NET Core and Visual Studio. In its words: “Microsoft .NET Core and Visual Studio contain an unspecified vulnerability that allows for denial-of-service (DoS).”[1]
The underlying weakness is resource exhaustion (CWE-400), in MITRE’s list of common software weaknesses.[2]
It scores 7.5 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| .NET 6.0 | 6.0.21 |
| .NET 7.0 | 7.0.10 |
| ASP.NET Core 2.1 | 2.1.40 |
| Microsoft Visual Studio 2022 version 17.2 | 17.2.18 |
| Microsoft Visual Studio 2022 version 17.4 | 17.4.10 |
| Microsoft Visual Studio 2022 version 17.6 | 17.6.6 |
Most families won’t have Microsoft .NET Core and Visual Studio; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 9 Aug 2023, within a day of it being made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 30 Aug 2023 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 14%. That’s in the top 4% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Microsoft .NET Core and Visual Studio is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 6.0.21, 7.0.10, 2.1.40 and 17.2.18 and others), or not in use. CISA gave US government agencies until 30 Aug 2023 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 14%.[4] |
See also
Other Microsoft flaws
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2026-65660, Microsoft SharePoint: code injection ·
- CVE-2026-85880, Microsoft Windows: heap-based buffer overflow ·
- CVE-2026-81963, Microsoft Windows: link following ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
Other resource exhaustion flaws
- CVE-2026-28318, SolarWinds Serv-U: uncontrolled resource consumption ·
- CVE-2023-44487, IETF HTTP/2: rapid reset attack ·
- CVE-2004-1464, Cisco IOS: denial-of-service ·
- CVE-2020-3569, Cisco IOS XR: software DVMRP memory exhaustion ·
- CVE-2020-3566, Cisco IOS XR: software DVMRP memory exhaustion ·
Every Microsoft flaw on CISA’s list · Everything added in August 2023
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft .NET Core and Visual Studio Denial-of-Service Vulnerability”. Known Exploited Vulnerabilities Catalog, added 9 Aug 2023.
- ^ National Institute of Standards and Technology. “CVE-2023-38180 Detail”. National Vulnerability Database, published 8 Aug 2023.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.141, percentile 96.6, 31 Oct 2026.
- CVE Program. “CVE-2023-38180”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.