What is GHSA-GMC6-FWG3-75M5?

GHSA-GMC6-FWG3-75M5 is a high-severity improper input validation vulnerability in MimeKit (nuget), affecting versions >= 3.0.0, < 4.7.1. It is fixed in 4.7.1. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.

How severe is GHSA-GMC6-FWG3-75M5?

GHSA-GMC6-FWG3-75M5 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 versions of MimeKit are affected by GHSA-GMC6-FWG3-75M5?

MimeKit (nuget) versions >= 3.0.0, < 4.7.1 is affected.

Is there a fix for GHSA-GMC6-FWG3-75M5?

Yes. GHSA-GMC6-FWG3-75M5 is fixed in 4.7.1. Upgrade to this version or later.

Is GHSA-GMC6-FWG3-75M5 exploitable, and should I be worried?

Whether GHSA-GMC6-FWG3-75M5 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.

What actually determines whether GHSA-GMC6-FWG3-75M5 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.

GHSA-GMC6-FWG3-75M5 in MimeKit

Q: How severe is GHSA-GMC6-FWG3-75M5?

GHSA-GMC6-FWG3-75M5 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.

Q: Which versions of MimeKit are affected by GHSA-GMC6-FWG3-75M5?

MimeKit (nuget) versions >= 3.0.0, < 4.7.1 is affected.

Q: Is there a fix for GHSA-GMC6-FWG3-75M5?

Yes. GHSA-GMC6-FWG3-75M5 is fixed in 4.7.1. Upgrade to this version or later.

Q: Is GHSA-GMC6-FWG3-75M5 exploitable, and should I be worried?

Whether GHSA-GMC6-FWG3-75M5 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.

Q: What actually determines whether GHSA-GMC6-FWG3-75M5 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.

Q: How do I fix GHSA-GMC6-FWG3-75M5?

Upgrade MimeKit to 4.7.1 or later.

Summary

Mimekit has vulnerable dependency that can lead to denial of service

Denial of service vulnerability.

Details

See: https://github.com/advisories/GHSA-447r-wph3-92pm and https://github.com/dotnet/announcements/issues/312

PoC

Update System.Security.Cryptography.Pkcs to 8.0.1 so that the transitive dependency with the issue gets updated

Impact

Denial of service vulnerability. Affects MimeKit (>= v3.0.0 and <= v4.7.0) when used to decrypt or verify incoming S/MIME messages as well as importing 3rd-party X.509 certificates for use with encrypting outgoing S/MIME messages.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

GHSA-GMC6-FWG3-75M5 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 (4.7.1); upgrading removes the vulnerable code path.

Affected versions

MimeKit (>= 3.0.0, < 4.7.1)

Security releases

MimeKit → 4.7.1 (nuget)

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.

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Remediation advice

Upgrade MimeKit to 4.7.1 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is GHSA-GMC6-FWG3-75M5? GHSA-GMC6-FWG3-75M5 is a high-severity improper input validation vulnerability in MimeKit (nuget), affecting versions >= 3.0.0, < 4.7.1. It is fixed in 4.7.1. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
How severe is GHSA-GMC6-FWG3-75M5? GHSA-GMC6-FWG3-75M5 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 versions of MimeKit are affected by GHSA-GMC6-FWG3-75M5? MimeKit (nuget) versions >= 3.0.0, < 4.7.1 is affected.
Is there a fix for GHSA-GMC6-FWG3-75M5? Yes. GHSA-GMC6-FWG3-75M5 is fixed in 4.7.1. Upgrade to this version or later.
Is GHSA-GMC6-FWG3-75M5 exploitable, and should I be worried? Whether GHSA-GMC6-FWG3-75M5 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 GHSA-GMC6-FWG3-75M5 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 GHSA-GMC6-FWG3-75M5? Upgrade MimeKit to 4.7.1 or later.

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