What is CVE-2020-35858?

CVE-2020-35858 is a critical-severity out-of-bounds write vulnerability in prost (rust), affecting versions < 0.6.1. It is fixed in 0.6.1. A write operation targets a memory location beyond the intended buffer boundary.

How severe is CVE-2020-35858?

CVE-2020-35858 has a CVSS score of 9.8 (Critical). 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 prost are affected by CVE-2020-35858?

prost (rust) versions < 0.6.1 is affected.

Is there a fix for CVE-2020-35858?

Yes. CVE-2020-35858 is fixed in 0.6.1. Upgrade to this version or later.

Is CVE-2020-35858 exploitable, and should I be worried?

Whether CVE-2020-35858 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-2020-35858 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-2020-35858 in prost

Q: How severe is CVE-2020-35858?

CVE-2020-35858 has a CVSS score of 9.8 (Critical). 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 prost are affected by CVE-2020-35858?

prost (rust) versions < 0.6.1 is affected.

Q: Is there a fix for CVE-2020-35858?

Yes. CVE-2020-35858 is fixed in 0.6.1. Upgrade to this version or later.

Q: Is CVE-2020-35858 exploitable, and should I be worried?

Whether CVE-2020-35858 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-2020-35858 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-2020-35858?

Upgrade prost to 0.6.1 or later.

Summary

Out of bounds write in prost

Affected versions of this crate contained a bug in which decoding untrusted input could overflow the stack. On architectures with stack probes (like x86), this can be used for denial of service attacks, while on architectures without stack probes (like ARM) overflowing the stack is unsound and can result in potential memory corruption (or even RCE).

Impact

A write operation targets a memory location beyond the intended buffer boundary. Typical impact: memory corruption, crash, or arbitrary code execution.

CVE-2020-35858 has a CVSS score of 9.8 (Critical). 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 (0.6.1); upgrading removes the vulnerable code path.

Affected versions

prost (< 0.6.1)

Security releases

prost → 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 prost 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-2020-35858? CVE-2020-35858 is a critical-severity out-of-bounds write vulnerability in prost (rust), affecting versions < 0.6.1. It is fixed in 0.6.1. A write operation targets a memory location beyond the intended buffer boundary.
How severe is CVE-2020-35858? CVE-2020-35858 has a CVSS score of 9.8 (Critical). 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 prost are affected by CVE-2020-35858? prost (rust) versions < 0.6.1 is affected.
Is there a fix for CVE-2020-35858? Yes. CVE-2020-35858 is fixed in 0.6.1. Upgrade to this version or later.
Is CVE-2020-35858 exploitable, and should I be worried? Whether CVE-2020-35858 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-2020-35858 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-2020-35858? Upgrade prost to 0.6.1 or later.