CVE-2019-0820 Regular Expression Denial of Service in System.Text.RegularExpressions
Attackers can cause a denial of service by submitting specially crafted regular expression strings to applications using .NET Framework or Core.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-0820?
CVE-2019-0820 is a high-severity denial of service vulnerability in Microsoft .Net Framework, published on 16 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A denial of service vulnerability exists when .NET Framework and .NET Core improperly process RegEx strings, aka '.NET Framework and .NET Core Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0980, CVE-2019-0981.
Weakness: CWE-400
Which versions are affected by CVE-2019-0820?
2 open source packages ship an affected version, including System.Text.RegularExpressions. It affects 6 products.
| Package | Affected | Fixed in |
|---|---|---|
System.Text.RegularExpressions NuGet | From 4.3.0 | 4.3.1 |
System.Text.RegularExpressions NuGet | From 4.3.0 | 4.3.1 |
Products include Microsoft .Net Core, Microsoft .Net Framework, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus.
How do I fix CVE-2019-0820?
Upgrade System.Text.RegularExpressions to 4.3.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2019-0820 being exploited?
There is no known exploitation of CVE-2019-0820 in the wild and no public exploit code.
Other vulnerabilities in Microsoft .Net Framework
- CVE-2020-1147 Microsoft .NET Framework, SharePoint, and Visual Studio Remote Code Execution
- CVE-2020-0605 Code injection in .NET Core
- CVE-2020-0606 Remote code execution in Microsoft.WindowsDesktop.App.Ref
- CVE-2019-1301 High severity vulnerability that affects System.Management.Automation
- CVE-2019-0980 Denial of service in ASP.NET Core
Sources
Also known as ECHO-495f-20f1-b39d, GHSA-cmhx-cq75-c4mj.