CVE-2020-15136
MEDIUMCVE-2020-15136 is a medium-severity (CVSS 6.5) Improper Authentication vulnerability in go.etcd.io/etcd. O3 Security confirms whether CVE-2020-15136 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Etcd Gateway TLS authentication only applies to endpoints detected in DNS SRV records
Blast Radius
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 | 3.4.10 |
| 🐹Go | go.etcd.io/etcd | all versions | 3.3.23 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 pinpoints whether CVE-2020-15136 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
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.
Frequently Asked Questions
Is CVE-2020-15136 in your dependencies?
O3 detects CVE-2020-15136 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.