CVE-2021-21278

CVE-2021-21278 is a high-severity security vulnerability in rsshub (npm), affecting versions <= 1.0.0. No fixed version is listed yet.

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Runtime intelligence, not another scanner.

Summary

Risk of code injection

Credits

Tencent Woodpecker Security Team

For more information

If you have any questions or comments about this advisory:

Impact

Some routes use eval or Function constructor, which may be injected by the target site with unsafe code, causing server-side security issues

CVE-2021-21278 has a CVSS score of 8.6 (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. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Affected versions

rsshub (<= 1.0.0)

Security releases

Not available

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

Temporarily removed the problematic route and added a no-new-func rule to eslint
Self-built users should upgrade to 7f1c430 and later as soon as possible

Frequently Asked Questions

  1. What is CVE-2021-21278? CVE-2021-21278 is a high-severity security vulnerability in rsshub (npm), affecting versions <= 1.0.0. No fixed version is listed yet.
  2. How severe is CVE-2021-21278? CVE-2021-21278 has a CVSS score of 8.6 (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.
  3. Which versions of rsshub are affected by CVE-2021-21278? rsshub (npm) versions <= 1.0.0 is affected.
  4. Is there a fix for CVE-2021-21278? No fixed version is listed for CVE-2021-21278 yet. Monitor the advisory for updates and apply mitigations in the interim.
  5. Is CVE-2021-21278 exploitable, and should I be worried? Whether CVE-2021-21278 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
  6. What actually determines whether CVE-2021-21278 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.

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