Summary
Etcd Gateway TLS authentication only applies to endpoints detected in DNS SRV records
Vulnerability type
Cryptography
Workarounds
Refer to the gateway documentation. The vulnerability was spotted due to unclear documentation of how the gateway handles endpoints validation.
Detail
When starting a gateway, TLS authentication will only be attempted on endpoints identified in DNS SRV records for a given domain, which occurs in the discoverEndpoints function. No authentication is performed against endpoints provided in the --endpoints flag. The auditors has noted that appropriate documentation of this validation functionality plus deprecation of this misleading functionality is an acceptable path forward.
References
Find out more on this vulnerability in the security audit report
For more information
If you have any questions or comments about this advisory:
- Contact the etcd security committee
Impact
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
CVE-2020-15136 has a CVSS score of 6.5 (Medium). 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 (3.4.10, 3.3.23); 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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go.etcd.io/etcd to 3.4.10 or later; go.etcd.io/etcd to 3.3.23 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2020-15136? CVE-2020-15136 is a medium-severity improper authentication vulnerability in go.etcd.io/etcd (go), affecting versions >= 3.4.0-rc.0, <= 3.4.9. It is fixed in 3.4.10, 3.3.23. The application does not adequately verify the identity of a user, device, or process before granting access.
- How severe is CVE-2020-15136? CVE-2020-15136 has a CVSS score of 6.5 (Medium). 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 go.etcd.io/etcd are affected by CVE-2020-15136? go.etcd.io/etcd (go) versions >= 3.4.0-rc.0, <= 3.4.9 is affected.
- Is there a fix for CVE-2020-15136? Yes. CVE-2020-15136 is fixed in 3.4.10, 3.3.23. Upgrade to this version or later.
- Is CVE-2020-15136 exploitable, and should I be worried? Whether CVE-2020-15136 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-2020-15136 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-2020-15136?
- Upgrade
go.etcd.io/etcdto 3.4.10 or later - Upgrade
go.etcd.io/etcdto 3.3.23 or later
- Upgrade