Summary
OpenStack Neutron Denial of Service vulnerability
An issue was discovered in the routes middleware in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1. By making API requests involving nonexistent controllers, an authenticated user may cause the API worker to consume increasing amounts of memory, resulting in API performance degradation or denial of service.
Impact
CVE-2021-40797 has a CVSS score of 6.5 (High). The vector is network-reachable, 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 (16.4.1, 17.2.1, 18.1.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
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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neutron to 16.4.1 or later; neutron to 17.2.1 or later; neutron to 18.1.1 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-40797? CVE-2021-40797 is a high-severity security vulnerability in neutron (pip), affecting versions < 16.4.1. It is fixed in 16.4.1, 17.2.1, 18.1.1.
- How severe is CVE-2021-40797? CVE-2021-40797 has a CVSS score of 6.5 (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 neutron are affected by CVE-2021-40797? neutron (pip) versions < 16.4.1 is affected.
- Is there a fix for CVE-2021-40797? Yes. CVE-2021-40797 is fixed in 16.4.1, 17.2.1, 18.1.1. Upgrade to this version or later.
- Is CVE-2021-40797 exploitable, and should I be worried? Whether CVE-2021-40797 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-2021-40797 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-2021-40797?
- Upgrade
neutronto 16.4.1 or later - Upgrade
neutronto 17.2.1 or later - Upgrade
neutronto 18.1.1 or later
- Upgrade