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Vulnerability details: VCID-axvm-3dh9-3kf6
Vulnerability ID VCID-axvm-3dh9-3kf6
Aliases CVE-2017-0247
GHSA-6xh7-4v2w-36q6
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-20 Improper Input Validation
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-707 Improper Neutralization
System Score Found at
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
epss 0.11122 https://api.first.org/data/v1/epss?cve=CVE-2017-0247
cvssv3.1 7.5 https://github.com/advisories/GHSA-6xh7-4v2w-36q6
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-6xh7-4v2w-36q6
generic_textual HIGH https://github.com/advisories/GHSA-6xh7-4v2w-36q6
cvssv3.1 7.5 https://github.com/aspnet/Announcements/issues/239
generic_textual HIGH https://github.com/aspnet/Announcements/issues/239
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2017-0247
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2017-0247
cvssv3.1 7.5 https://technet.microsoft.com/en-us/library/security/4021279.aspx
generic_textual HIGH https://technet.microsoft.com/en-us/library/security/4021279.aspx
cvssv3.1 7.5 https://www.sidertia.com/Home/Community/Blog/2017/05/18/ASPNET-Core-Unicode-Non-Char-Encoding-DoS
generic_textual HIGH https://www.sidertia.com/Home/Community/Blog/2017/05/18/ASPNET-Core-Unicode-Non-Char-Encoding-DoS
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2017-0247
https://github.com/aspnet/Announcements/issues/239
https://technet.microsoft.com/en-us/library/security/4021279.aspx
https://www.sidertia.com/Home/Community/Blog/2017/05/18/ASPNET-Core-Unicode-Non-Char-Encoding-DoS
CVE-2017-0247 https://nvd.nist.gov/vuln/detail/CVE-2017-0247
GHSA-6xh7-4v2w-36q6 https://github.com/advisories/GHSA-6xh7-4v2w-36q6
No exploits are available.
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/advisories/GHSA-6xh7-4v2w-36q6
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/aspnet/Announcements/issues/239
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2017-0247
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://technet.microsoft.com/en-us/library/security/4021279.aspx
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://www.sidertia.com/Home/Community/Blog/2017/05/18/ASPNET-Core-Unicode-Non-Char-Encoding-DoS
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.93431
EPSS Score 0.11122
Published At April 1, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:47:14.238508+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/nuget/Microsoft.AspNet.Mvc/CVE-2017-0247.yml 38.0.0