CVE-2021-33880

CVE-2021-33880 is a high-severity security vulnerability in websockets (pip), affecting versions < 9.1. It is fixed in 9.1.

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Runtime intelligence, not another scanner.

Summary

Observable Timing Discrepancy in aaugustin websockets library

The aaugustin websockets library before 9.1 for Python has an Observable Timing Discrepancy on servers when HTTP Basic Authentication is enabled with basic_auth_protocol_factory(credentials=...). An attacker may be able to guess a password via a timing attack.

Impact

CVE-2021-33880 has a CVSS score of 5.9 (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 (9.1); upgrading removes the vulnerable code path.

Affected versions

websockets (< 9.1)

Security releases

websockets → 9.1 (pip)

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 websockets to 9.1 or later to resolve this vulnerability.

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

Frequently Asked Questions

  1. What is CVE-2021-33880? CVE-2021-33880 is a high-severity security vulnerability in websockets (pip), affecting versions < 9.1. It is fixed in 9.1.
  2. How severe is CVE-2021-33880? CVE-2021-33880 has a CVSS score of 5.9 (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 websockets are affected by CVE-2021-33880? websockets (pip) versions < 9.1 is affected.
  4. Is there a fix for CVE-2021-33880? Yes. CVE-2021-33880 is fixed in 9.1. Upgrade to this version or later.
  5. Is CVE-2021-33880 exploitable, and should I be worried? Whether CVE-2021-33880 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-2021-33880 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.
  7. How do I fix CVE-2021-33880? Upgrade websockets to 9.1 or later.

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