Summary
Improper Certificate Validation
.NET Core 1.0, 1.1, and 2.0 allow an unauthenticated attacker to remotely cause a denial of service attack against a .NET Core web application by improperly parsing certificate data. A denial of service vulnerability exists when .NET Core improperly handles parsing certificate data, aka ".NET CORE Denial Of Service Vulnerability".
Impact
CVE-2017-11770 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.2, 2.0.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
System.Security.Cryptography.X509Certificates to 4.1.2 or later; Microsoft.NETCore.App to 2.0.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2017-11770? CVE-2017-11770 is a high-severity security vulnerability in System.Security.Cryptography.X509Certificates (nuget), affecting versions >= 4.0.0, < 4.1.2. It is fixed in 4.1.2, 2.0.3.
- How severe is CVE-2017-11770? CVE-2017-11770 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2017-11770?
System.Security.Cryptography.X509Certificates(nuget) (versions >= 4.0.0, < 4.1.2)Microsoft.NETCore.App(nuget) (versions >= 1.0.0, < 2.0.3)
- Is there a fix for CVE-2017-11770? Yes. CVE-2017-11770 is fixed in 4.1.2, 2.0.3. Upgrade to this version or later.
- Is CVE-2017-11770 exploitable, and should I be worried? Whether CVE-2017-11770 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2017-11770 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2017-11770?
- Upgrade
System.Security.Cryptography.X509Certificatesto 4.1.2 or later - Upgrade
Microsoft.NETCore.Appto 2.0.3 or later
- Upgrade