What is CVE-2019-25103?

CVE-2019-25103 is a high-severity inefficient regular expression (ReDoS) vulnerability in simple-markdown (npm), affecting versions < 0.5.2. It is fixed in 0.5.2. A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use.

How severe is CVE-2019-25103?

CVE-2019-25103 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 simple-markdown are affected by CVE-2019-25103?

simple-markdown (npm) versions < 0.5.2 is affected.

Is there a fix for CVE-2019-25103?

Yes. CVE-2019-25103 is fixed in 0.5.2. Upgrade to this version or later.

Is CVE-2019-25103 exploitable, and should I be worried?

Whether CVE-2019-25103 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-2019-25103 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-2019-25103 in simple-markdown

Q: How severe is CVE-2019-25103?

CVE-2019-25103 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 simple-markdown are affected by CVE-2019-25103?

simple-markdown (npm) versions < 0.5.2 is affected.

Q: Is there a fix for CVE-2019-25103?

Yes. CVE-2019-25103 is fixed in 0.5.2. Upgrade to this version or later.

Q: Is CVE-2019-25103 exploitable, and should I be worried?

Whether CVE-2019-25103 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-2019-25103 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-2019-25103?

Upgrade simple-markdown to 0.5.2 or later.

Summary

Regular Expression Denial of Service in simple-markdown

A vulnerability has been found in simple-markdown 0.5.1 and classified as problematic. Affected by this vulnerability is an unknown functionality of the file simple-markdown.js. The manipulation leads to inefficient regular expression complexity. The attack can be launched remotely. Upgrading to version 0.5.2 is able to address this issue. The name of the patch is 89797fef9abb4cab2fb76a335968266a92588816. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-220639.

Impact

A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use. Typical impact: denial of service when input is crafted to trigger backtracking.

CVE-2019-25103 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 (0.5.2); upgrading removes the vulnerable code path.

Affected versions

simple-markdown (< 0.5.2)

Security releases

simple-markdown → 0.5.2 (npm)

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 simple-markdown to 0.5.2 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-2019-25103? CVE-2019-25103 is a high-severity inefficient regular expression (ReDoS) vulnerability in simple-markdown (npm), affecting versions < 0.5.2. It is fixed in 0.5.2. A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use.
How severe is CVE-2019-25103? CVE-2019-25103 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 simple-markdown are affected by CVE-2019-25103? simple-markdown (npm) versions < 0.5.2 is affected.
Is there a fix for CVE-2019-25103? Yes. CVE-2019-25103 is fixed in 0.5.2. Upgrade to this version or later.
Is CVE-2019-25103 exploitable, and should I be worried? Whether CVE-2019-25103 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-2019-25103 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-2019-25103? Upgrade simple-markdown to 0.5.2 or later.

Other vulnerabilities in simple-markdown

CVE-IDSeverityPackage summary

CVE-2019-25102Highsimple-markdown: Regular Expression Denial of Service in simple-markdown CVE-2019-9844Mediumsimple-markdown: Cross-Site Scripting in simple-markdown