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Package details: pkg:nuget/System.Text.Encodings.Web@4.3.1
purl pkg:nuget/System.Text.Encodings.Web@4.3.1
Next non-vulnerable version 4.5.1
Latest non-vulnerable version 5.0.1
Risk 4.5
Vulnerabilities affecting this package (1)
Vulnerability Summary Fixed by
VCID-bd3c-1sg9-wfh2
Aliases:
CVE-2021-26701
GHSA-ghhp-997w-qr28
.NET Core Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-24112. ### Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 5.0, .NET Core 3.1, and .NET Core 2.1. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A remote code execution vulnerability exists in .NET 5 and .NET Core due to how text encoding is performed. ### Discussion Discussion for this issue can be found at dotnet/runtime#49377 ### Mitigation factors Microsoft has not identified any mitigating factors for this vulnerability. ### Affected software The vulnerable package is `System.Text.Encodings.Web` . Upgrading your package and redeploying your app should be sufficient to address this vulnerability. Vulnerable package versions: Any .NET 5, .NET Core, or .NET Framework based application that uses the System.Text.Encodings.Web package with a vulnerable version listed below. Package Name | Vulnerable Versions | Secure Versions -|-|- System.Text.Encodings.Web | 4.0.0 - 4.5.0 | 4.5.1 System.Text.Encodings.Web | 4.6.0-4.7.1 | 4.7.2 System.Text.Encodings.Web | 5.0.0 | 5.0.1 Please validate that each of the .NET versions you are using is in support. Security updates are only provided for supported .NET versions.
4.5.1
Affected by 0 other vulnerabilities.
4.7.2
Affected by 0 other vulnerabilities.
5.0.1
Affected by 0 other vulnerabilities.
Vulnerabilities fixed by this package (4)
Vulnerability Summary Aliases
VCID-axvm-3dh9-3kf6 Improper Input Validation A denial of service vulnerability exists when the ASP.NET Core fails to properly validate web requests. NOTE: Microsoft has not commented on third-party claims that the issue is that the TextEncoder.EncodeCore function in the System.Text.Encodings.Web package in ASP.NET Core Mvc allows remote attackers to cause a denial of service by leveraging failure to properly calculate the length of 4-byte characters in the Unicode Non-Character range. CVE-2017-0247
GHSA-6xh7-4v2w-36q6
VCID-b2mg-kc6t-z7ht Improper Input Validation A spoofing vulnerability exists when the ASP.NET Core fails to properly sanitize web requests. CVE-2017-0256
GHSA-j8f4-2w4p-mhjc
VCID-j4d8-wr24-63d3 Improper Certificate Validation Microsoft .NET Framework 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2 and 4.7 allow an attacker to bypass Enhanced Security Usage taggings when they present a certificate that is invalid for a specific use, aka ".NET Security Feature Bypass Vulnerability." CVE-2017-0248
GHSA-ch6p-4jcm-h8vh
VCID-mrpr-pw4n-bfae Improper Input Validation An elevation of privilege vulnerability exists when the ASP.NET Core fails to properly sanitize web requests. CVE-2017-0249
GHSA-qhqf-ghgh-x2m4

Date Actor Action Vulnerability Source VulnerableCode Version
2026-04-16T21:21:29.779304+00:00 GitLab Importer Affected by VCID-bd3c-1sg9-wfh2 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2021-26701.yml 38.4.0
2026-04-16T20:48:44.223998+00:00 GitLab Importer Fixing VCID-b2mg-kc6t-z7ht https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0256.yml 38.4.0
2026-04-16T20:48:36.452650+00:00 GitLab Importer Fixing VCID-j4d8-wr24-63d3 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0248.yml 38.4.0
2026-04-16T20:48:13.692885+00:00 GitLab Importer Fixing VCID-mrpr-pw4n-bfae https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0249.yml 38.4.0
2026-04-16T20:48:06.724456+00:00 GitLab Importer Fixing VCID-axvm-3dh9-3kf6 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0247.yml 38.4.0
2026-04-11T22:33:58.489223+00:00 GitLab Importer Affected by VCID-bd3c-1sg9-wfh2 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2021-26701.yml 38.3.0
2026-04-11T21:59:39.810860+00:00 GitLab Importer Fixing VCID-b2mg-kc6t-z7ht https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0256.yml 38.3.0
2026-04-11T21:59:31.914069+00:00 GitLab Importer Fixing VCID-j4d8-wr24-63d3 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0248.yml 38.3.0
2026-04-11T21:59:05.177656+00:00 GitLab Importer Fixing VCID-mrpr-pw4n-bfae https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0249.yml 38.3.0
2026-04-11T21:58:58.872520+00:00 GitLab Importer Fixing VCID-axvm-3dh9-3kf6 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0247.yml 38.3.0
2026-04-02T22:45:04.301040+00:00 GitLab Importer Affected by VCID-bd3c-1sg9-wfh2 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2021-26701.yml 38.1.0
2026-04-02T22:12:51.257441+00:00 GitLab Importer Fixing VCID-b2mg-kc6t-z7ht https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0256.yml 38.1.0
2026-04-02T22:12:43.800778+00:00 GitLab Importer Fixing VCID-j4d8-wr24-63d3 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0248.yml 38.1.0
2026-04-02T22:12:23.601195+00:00 GitLab Importer Fixing VCID-mrpr-pw4n-bfae https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0249.yml 38.1.0
2026-04-02T22:12:17.226582+00:00 GitLab Importer Fixing VCID-axvm-3dh9-3kf6 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0247.yml 38.1.0
2026-04-01T17:03:02.469967+00:00 GitLab Importer Affected by VCID-bd3c-1sg9-wfh2 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2021-26701.yml 38.0.0
2026-04-01T15:56:50.039542+00:00 GHSA Importer Fixing VCID-j4d8-wr24-63d3 https://github.com/advisories/GHSA-ch6p-4jcm-h8vh 38.0.0
2026-04-01T15:56:48.882629+00:00 GHSA Importer Fixing VCID-axvm-3dh9-3kf6 https://github.com/advisories/GHSA-6xh7-4v2w-36q6 38.0.0
2026-04-01T15:56:47.407109+00:00 GHSA Importer Fixing VCID-b2mg-kc6t-z7ht https://github.com/advisories/GHSA-j8f4-2w4p-mhjc 38.0.0
2026-04-01T15:56:47.282539+00:00 GHSA Importer Fixing VCID-mrpr-pw4n-bfae https://github.com/advisories/GHSA-qhqf-ghgh-x2m4 38.0.0
2026-04-01T13:03:35.409712+00:00 GithubOSV Importer Fixing VCID-b2mg-kc6t-z7ht https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2018/10/GHSA-j8f4-2w4p-mhjc/GHSA-j8f4-2w4p-mhjc.json 38.0.0
2026-04-01T13:03:34.163164+00:00 GithubOSV Importer Fixing VCID-axvm-3dh9-3kf6 https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2018/10/GHSA-6xh7-4v2w-36q6/GHSA-6xh7-4v2w-36q6.json 38.0.0
2026-04-01T13:03:33.565387+00:00 GithubOSV Importer Fixing VCID-mrpr-pw4n-bfae https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2018/10/GHSA-qhqf-ghgh-x2m4/GHSA-qhqf-ghgh-x2m4.json 38.0.0
2026-04-01T13:03:20.108756+00:00 GithubOSV Importer Fixing VCID-j4d8-wr24-63d3 https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2018/10/GHSA-ch6p-4jcm-h8vh/GHSA-ch6p-4jcm-h8vh.json 38.0.0
2026-04-01T12:48:02.585553+00:00 GitLab Importer Fixing VCID-b2mg-kc6t-z7ht https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0256.yml 38.0.0
2026-04-01T12:48:02.071046+00:00 GitLab Importer Fixing VCID-j4d8-wr24-63d3 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0248.yml 38.0.0
2026-04-01T12:48:00.708242+00:00 GitLab Importer Fixing VCID-mrpr-pw4n-bfae https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0249.yml 38.0.0
2026-04-01T12:48:00.162539+00:00 GitLab Importer Fixing VCID-axvm-3dh9-3kf6 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/System.Text.Encodings.Web/CVE-2017-0247.yml 38.0.0