CVE-2020-15136 — etcd
MEDIUMCVE-2020-15136 is a medium-severity (CVSS 6.5) vulnerability in go.etcd.io/etcd. A fix is available for go.etcd.io/etcd — see the affected versions and patch details below.
Etcd Gateway TLS authentication only applies to endpoints detected in DNS SRV records
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2020-15136 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
go.etcd.io/etcd🐹go.etcd.io/etcdReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
In ectd before versions 3.4.10 and 3.3.23, gateway TLS authentication is only applied to endpoints detected in DNS SRV records. 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. This has been fixed in versions 3.4.10 and 3.3.23 with improved documentation and deprecation of the functionality.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | go.etcd.io/etcd | ≥ 3.4.0-rc.0&&< 3.4.10 | 3.4.10go get go.etcd.io/etcd@v3.4.10 |
| 🐹Go | go.etcd.io/etcd | all versions | 3.3.23go get go.etcd.io/etcd@v3.3.23 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.etcd.io/etcd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.etcd.io/etcd to 3.4.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-15136 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-15136 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-15136. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
In Red Hat OpenShift Container Platform (RHOCP) the affected components are behind OpenShift OAuth authentication. This restricts access to the vulnerable etcd to authenticated users only, therefore the impact by this vulnerability is Low. A similar access restriction is in place in Red Hat OpenStack Platform (RHOSP)…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 4.8 | openshift4/ose-etcd:v4.8.0-202106152230.p0.git.aefa6bf.assembly.stream | RHSA-2021:2438 |
| Red Hat OpenStack Platform 16.1 | etcd-0:3.3.23-1.el8ost | RHSA-2021:0916 |
Frequently Asked Questions
Is CVE-2020-15136 in your dependencies?
O3 Security finds CVE-2020-15136 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.