How severe is CVE-2020-15136?

CVE-2020-15136 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-15136?

CVE-2020-15136 affects the following packages: go.etcd.io/etcd (Go), go.etcd.io/etcd (Go). Ecosystems affected: Go.

How do I fix CVE-2020-15136?

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.

How do I detect CVE-2020-15136 in my Go dependencies?

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.

How do I mitigate CVE-2020-15136 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2020-15136 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-15136 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-15136?

CVE-2020-15136 has an EPSS (Exploit Prediction Scoring System) score of 1.7%, placing it in the 77th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-15136?

CVE-2020-15136 is classified as Improper Authentication (CWE-287), Missing Authentication (CWE-306). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2020-15136 published, and has it been updated?

CVE-2020-15136 was published on August 6, 2020 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2020-15136 — etcd

MEDIUM

CVE-2020-15136 is a medium-severity (CVSS 6.5) Improper Authentication 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

Also known asGHSA-wr2v-9rpq-c35q

Published

Aug 6, 2020

Updated

Oct 20, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.7%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs77th percentile — riskier than 77% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐹go.etcd.io/etcd🐹go.etcd.io/etcd

Real-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

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

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.etcd.io/etcd`	≥ 3.4.0-rc.0&&< 3.4.10	3.4.10`go get go.etcd.io/etcd@v3.4.10`
🐹Go	`go.etcd.io/etcd`	all versions	3.3.23`go get go.etcd.io/etcd@v3.3.23`

Affected Products

2 products · 3 configurations

fedorafedoraproject

1 version

Application

etcdredhat

≥ 3.4.0 && < 3.4.10

range

Detection & mitigation playbook

Open-source dependency

Detect
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
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

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.

Red HatModerate

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

### Vulnerability type Cryptography ### Workarounds Refer to the [gateway documentation](https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/gateway.md). 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 documenta