CVE-2019-0820
Regular Expression Denial of Service in System.Text.RegularExpressions
7.5 HighFix available
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
5.72%Down 2.5 points since Apr 14, 2021
What each source reports
NVD Score used
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.
- Record
CVE-2019-0820- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2019-0820- Updated
- 2026-11-02
EUVDEUVD-2021-1682 No score
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.
- Record
EUVD-2021-1682- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cmhx-cq75-c4mj
Regular Expression Denial of Service in System.Text.RegularExpressions
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.
- Record
GHSA-cmhx-cq75-c4mj- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400, CWE-1333
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2019-0820- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-cmhx-cq75-c4mj
Regular Expression Denial of Service in System.Text.RegularExpressions
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.
- Record
GHSA-cmhx-cq75-c4mj- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-1333, CWE-400
- Updated
- 2026-11-02
OSVRHSA-2019:1236
Red Hat Security Advisory: .NET Core on Red Hat Enterprise Linux security and bug fix update
- Record
RHSA-2019:1236- CVSS 3.0
- 7.5 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVRHSA-2019:1259
Red Hat Security Advisory: dotnet security, bug fix, and enhancement update
- Record
RHSA-2019:1259- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
- microsoft .net core
- microsoft .net framework
- microsoft .net framework 2.0
- microsoft .net framework 3.0
- microsoft .net framework 3.5
- microsoft .net framework 3.5 on windows 10 version 1903 for 32-bit systems
- microsoft .net framework 3.5 on windows 10 version 1903 for x64-based systems
- microsoft .net framework 3.5 on windows server, version 1903 (server core installation)
- microsoft .net framework 3.5.1
- microsoft .net framework 4.5.2
- microsoft .net framework 4.6
- microsoft .net framework 4.6.2/4.7/4.7.1/4.7.2
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- microsoft .net framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2
- microsoft .net framework 4.7.2
- microsoft .net framework 4.8 on windows 10 version 1607 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1607 for x64-based systems
- microsoft .net framework 4.8 on windows 10 version 1703 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1703 for x64-based systems
- microsoft .net framework 4.8 on windows 10 version 1709 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1709 for x64-based systems
- microsoft .net framework 4.8 on windows 10 version 1803 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1803 for x64-based systems
- microsoft .net framework 4.8 on windows 10 version 1809 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1809 for x64-based systems
- microsoft .net framework 4.8 on windows 10 version 1903 for 32-bit systems
- microsoft .net framework 4.8 on windows 10 version 1903 for x64-based systems
- microsoft .net framework 4.8 on windows 7 for 32-bit systems service pack 1
- microsoft .net framework 4.8 on windows 7 for x64-based systems service pack 1
- microsoft .net framework 4.8 on windows 8.1 for 32-bit systems
- microsoft .net framework 4.8 on windows 8.1 for x64-based systems
- microsoft .net framework 4.8 on windows rt 8.1
- microsoft .net framework 4.8 on windows server 2008 r2 for x64-based systems service pack 1
- microsoft .net framework 4.8 on windows server 2008 r2 for x64-based systems service pack 1 (server core installation)
- microsoft .net framework 4.8 on windows server 2012
- microsoft .net framework 4.8 on windows server 2012 (server core installation)
- microsoft .net framework 4.8 on windows server 2012 r2
- microsoft .net framework 4.8 on windows server 2012 r2 (server core installation)
- microsoft .net framework 4.8 on windows server 2016
- microsoft .net framework 4.8 on windows server 2016 (server core installation)
- microsoft .net framework 4.8 on windows server 2019
- microsoft .net framework 4.8 on windows server 2019 (server core installation)
- microsoft .net framework 4.8 on windows server, version 1803 (server core installation)
- microsoft .net framework 4.8 on windows server, version 1903 (server core installation)
- redhat enterprise linux
- redhat enterprise linux eus
- redhat enterprise linux server aus
- redhat enterprise linux server tus
Affected packages
| Package | Affected | Fixed |
|---|---|---|
System.Text.RegularExpressionsNuGet |
4.3.0 up to 4.3.1 | 4.3.1 |
rh-dotnetcore10-dotnetcoreRed Hat:rhel_dotnet:1.0::el7 From an advisory covering 3 CVEs |
before 0:1.0.16-1.el7 | 0:1.0.16-1.el7 |
rh-dotnetcore10-dotnetcore-debuginfoRed Hat:rhel_dotnet:1.0::el7 From an advisory covering 3 CVEs |
before 0:1.0.16-1.el7 | 0:1.0.16-1.el7 |
rh-dotnetcore11-dotnetcoreRed Hat:rhel_dotnet:1.1::el7 From an advisory covering 3 CVEs |
before 0:1.1.13-1.el7 | 0:1.1.13-1.el7 |
rh-dotnetcore11-dotnetcore-debuginfoRed Hat:rhel_dotnet:1.1::el7 From an advisory covering 3 CVEs |
before 0:1.1.13-1.el7 | 0:1.1.13-1.el7 |
rh-dotnet21Red Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1-10.el7 | 0:2.1-10.el7 |
rh-dotnet21-dotnetRed Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.507-2.el7 | 0:2.1.507-2.el7 |
rh-dotnet21-dotnet-debuginfoRed Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.507-2.el7 | 0:2.1.507-2.el7 |
rh-dotnet21-dotnet-hostRed Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.11-2.el7 | 0:2.1.11-2.el7 |
rh-dotnet21-dotnet-runtime-2.1Red Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.11-2.el7 | 0:2.1.11-2.el7 |
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| Package | Affected | Fixed |
|---|---|---|
rh-dotnet21-dotnet-sdk-2.1Red Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.507-2.el7 | 0:2.1.507-2.el7 |
rh-dotnet21-dotnet-sdk-2.1.5xxRed Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1.507-2.el7 | 0:2.1.507-2.el7 |
rh-dotnet21-runtimeRed Hat:rhel_dotnet:2.1::el7 From an advisory covering 3 CVEs |
before 0:2.1-10.el7 | 0:2.1-10.el7 |
rh-dotnet22Red Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2-7.el7 | 0:2.2-7.el7 |
rh-dotnet22-curlRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:7.61.1-2.el7 | 0:7.61.1-2.el7 |
rh-dotnet22-curl-debuginfoRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:7.61.1-2.el7 | 0:7.61.1-2.el7 |
rh-dotnet22-dotnetRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.107-2.el7 | 0:2.2.107-2.el7 |
rh-dotnet22-dotnet-debuginfoRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.107-2.el7 | 0:2.2.107-2.el7 |
rh-dotnet22-dotnet-hostRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.5-2.el7 | 0:2.2.5-2.el7 |
rh-dotnet22-dotnet-host-fxr-2.2Red Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.5-2.el7 | 0:2.2.5-2.el7 |
rh-dotnet22-dotnet-runtime-2.2Red Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.5-2.el7 | 0:2.2.5-2.el7 |
rh-dotnet22-dotnet-sdk-2.2Red Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.107-2.el7 | 0:2.2.107-2.el7 |
rh-dotnet22-dotnet-sdk-2.2.1xxRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2.107-2.el7 | 0:2.2.107-2.el7 |
rh-dotnet22-libcurlRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:7.61.1-2.el7 | 0:7.61.1-2.el7 |
rh-dotnet22-libcurl-develRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:7.61.1-2.el7 | 0:7.61.1-2.el7 |
rh-dotnet22-runtimeRed Hat:rhel_dotnet:2.2::el7 From an advisory covering 3 CVEs |
before 0:2.2-7.el7 | 0:2.2-7.el7 |
dotnetRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
dotnet-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
dotnet-debugsourceRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
dotnet-hostRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-host-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-host-fxr-2.1Red Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-host-fxr-2.1-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-runtime-2.1Red Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-runtime-2.1-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.11-2.el8_0 | 0:2.1.11-2.el8_0 |
dotnet-sdk-2.1Red Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
dotnet-sdk-2.1.5xxRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
dotnet-sdk-2.1.5xx-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 4 CVEs |
before 0:2.1.507-2.el8_0 | 0:2.1.507-2.el8_0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-0820 is a high vulnerability (CVSS 7.5) in Microsoft .net Core, published May 16, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 5.72%, the 93rd percentile. Fixed in System.Text.RegularExpressions 4.3.1.
References
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0820
access.redhat.com/errata/RHSA-2019:1259
nvd.nist.gov/vuln/detail/CVE-2019-0820
github.com/advisories/GHSA-cmhx-cq75-c4mj
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bugzilla.redhat.com/show_bug.cgi?id=1654863
security.access.redhat.com/data/csaf/v2/advisories/2019/rhsa-2019_1236.json
cve.org/CVERecord?id=CVE-2019-0820