What is CVE-2020-36203?

CVE-2020-36203 is a medium-severity race condition vulnerability in reffers (rust), affecting versions < 0.6.1. It is fixed in 0.6.1. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.

How severe is CVE-2020-36203?

CVE-2020-36203 has a CVSS score of 4.7 (Medium). 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 reffers are affected by CVE-2020-36203?

reffers (rust) versions < 0.6.1 is affected.

Is there a fix for CVE-2020-36203?

Yes. CVE-2020-36203 is fixed in 0.6.1. Upgrade to this version or later.

Is CVE-2020-36203 exploitable, and should I be worried?

Whether CVE-2020-36203 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 CVE-2020-36203 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.

CVE-2020-36203 in reffers

Q: How severe is CVE-2020-36203?

CVE-2020-36203 has a CVSS score of 4.7 (Medium). 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 reffers are affected by CVE-2020-36203?

reffers (rust) versions < 0.6.1 is affected.

Q: Is there a fix for CVE-2020-36203?

Yes. CVE-2020-36203 is fixed in 0.6.1. Upgrade to this version or later.

Q: Is CVE-2020-36203 exploitable, and should I be worried?

Whether CVE-2020-36203 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 CVE-2020-36203 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 CVE-2020-36203?

Upgrade reffers to 0.6.1 or later.

Summary

Data races in reffers

ARefss<'a, V> is a type that is assumed to contain objects that are Send + Sync.

In the affected versions of this crate, Send/Sync traits are unconditionally implemented for ARefss<'a, V>.

By using the ARefss::map() API, we can insert a !Send or !Sync object into ARefss<'a, V>. After that, it is possible to create a data race to the inner object of ARefss<'a, V>, which can lead to undefined behavior & memory corruption.

The flaw was corrected in commit 6dd7ca0 by adding trait bound V: Send + Sync to ARefss::map() API.

Impact

Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing. Typical impact: TOCTOU exploits, data corruption, or privilege escalation.

CVE-2020-36203 has a CVSS score of 4.7 (Medium). The vector is requires local access, low 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 (0.6.1); upgrading removes the vulnerable code path.

Affected versions

reffers (< 0.6.1)

Security releases

reffers → 0.6.1 (rust)

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 reffers to 0.6.1 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 CVE-2020-36203? CVE-2020-36203 is a medium-severity race condition vulnerability in reffers (rust), affecting versions < 0.6.1. It is fixed in 0.6.1. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.
How severe is CVE-2020-36203? CVE-2020-36203 has a CVSS score of 4.7 (Medium). 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 reffers are affected by CVE-2020-36203? reffers (rust) versions < 0.6.1 is affected.
Is there a fix for CVE-2020-36203? Yes. CVE-2020-36203 is fixed in 0.6.1. Upgrade to this version or later.
Is CVE-2020-36203 exploitable, and should I be worried? Whether CVE-2020-36203 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-2020-36203 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-2020-36203? Upgrade reffers to 0.6.1 or later.