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.NET
.NET NuGet
Not in CISA KEV
HIGH severity

CVE-2017-8700 — Microsoft.AspNetCore.Mvc.…

HIGH

CVE-2017-8700 is a high-severity (CVSS 7.5) vulnerability in Microsoft.AspNetCore.Mvc.Core. EPSS puts its 30-day exploitation probability at 10.4% (96th percentile). A fix is available for Microsoft.AspNetCore.Mvc.Core — see the affected versions and patch details below.

Cross-origin Resource Sharing bypass in ASP.NET Core

Also known asGHSA-3rp6-rjw4-cq39
Published
Updated
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed
Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
10.4%probability of exploitation in next 30 days
Moderate Risk-0.12%
Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk
6.46%8.11%9.76%11.4%7.4%10.4%May 26Aug 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected
.NETMicrosoft.AspNetCore.Mvc.Core.NETMicrosoft.AspNetCore.Mvc.Core.NETMicrosoft.AspNetCore.Mvc.Cors.NETMicrosoft.AspNetCore.Mvc.Cors

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

ASP.NET Core 1.0, 1.1, and 2.0 allow an attacker to bypass Cross-origin Resource Sharing (CORS) configurations and retrieve normally restricted content from a web application, aka "ASP.NET Core Information Disclosure Vulnerability".

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.AspNetCore.Mvc.Core≥ 1.0.0&&< 1.0.61.0.6dotnet add package Microsoft.AspNetCore.Mvc.Core --version 1.0.6
.NETNuGetMicrosoft.AspNetCore.Mvc.Core≥ 1.1.0&&< 1.1.61.1.6dotnet add package Microsoft.AspNetCore.Mvc.Core --version 1.1.6
.NETNuGetMicrosoft.AspNetCore.Mvc.Cors≥ 1.0.0&&< 1.0.61.0.6dotnet add package Microsoft.AspNetCore.Mvc.Cors --version 1.0.6
.NETNuGetMicrosoft.AspNetCore.Mvc.Cors≥ 1.1.0&&< 1.1.61.1.6dotnet add package Microsoft.AspNetCore.Mvc.Cors --version 1.1.6

Affected Products

1 product · 3 configurations
Application
asp.net coremicrosoft
3 versions
1.01.12.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.Mvc.Core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Microsoft.AspNetCore.Mvc.Core to 1.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-8700 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

ASP.NET Core 1.0, 1.1, and 2.0 allow an attacker to bypass Cross-origin Resource Sharing (CORS) configurations and retrieve normally restricted content from a web application, aka "ASP.NET Core Information Disclosure Vulnerability".
O3 Security · Impact-Aware SCA

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CVE-2017-8700: Microsoft.AspNetCore.Mvc — Fixed in 1.0.6