CVE-2020-15136 Improper authentication in etcd

Medium 6.5 Published 6 Aug 2020 Updated 4 Aug 2024

Attackers can bypass TLS authentication on etcd gateway endpoints specified via flags, potentially accessing sensitive data or services without proper credentials.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2020-15136?

CVE-2020-15136 is a medium-severity authentication bypass vulnerability in Fedoraproject Fedora, published on 6 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-306, CWE-287

Which versions are affected by CVE-2020-15136?

4 open source packages ship an affected version, including go.etcd.io/etcd. It affects 2 products.

Package	Affected	Fixed in
`go.etcd.io/etcd` Go	All versions	`3.3.23`
`go.etcd.io/etcd` Go	All versions	`3.3.23`
`go.etcd.io/etcd` Go	From `3.4.0-rc.0`	`3.4.10`
`go.etcd.io/etcd` Go	From `3.4.0-rc.0`	`3.4.10`

Products include Fedoraproject Fedora, Redhat Etcd.

How do I fix CVE-2020-15136?

Upgrade go.etcd.io/etcd to a fixed version for your release line: 3.3.23 or 3.4.10.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2020-15136 being exploited?

There is no known exploitation of CVE-2020-15136 in the wild and no public exploit code.

All Fedoraproject Fedora vulnerabilities

Sources

Also known as AZL-6393, CLEANSTART-2025-MN33948, DEBIAN-CVE-2020-15136, GHSA-wr2v-9rpq-c35q, UBUNTU-CVE-2020-15136.