What’s Vulnerable › Vulnerabilities

CVE-2018-16886

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-01-14 · updated 2026-06-17
• Weakness: CWE-287

Description

etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control (RBAC) is used and client-cert-auth is enabled. If an etcd client server TLS certificate contains a Common Name (CN) which matches a valid RBAC username, a remote attacker may authenticate as that user with any valid (trusted) client certificate in a REST API request to the gRPC-gateway.

Affected products

• etcd-io etcd: from 3.2.0 before 3.2.26; from 3.3.0 before 3.3.11 — fixed in 3.2.26, 3.3.11
• Fedoraproject Fedora: 30
• RedHat Enterprise Linux Desktop: 7.0
• RedHat Enterprise Linux Server: 7.0
• RedHat Enterprise Linux Workstation: 7.0

How to fix

Upgrade to a fixed version: etcd-io etcd 3.2.26, 3.3.11. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/106540
• https://access.redhat.com/errata/RHSA-2019:0237
• https://access.redhat.com/errata/RHSA-2019:1352
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886
• https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authentication
• https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authentication
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JX7QTIT465BQGRGNCE74RATRQLKT2QE4/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPGYHMSKDPW5GAMI7BEP3XQRVRLLBJKS/
• http://www.securityfocus.com/bid/106540
• https://access.redhat.com/errata/RHSA-2019:0237
• https://access.redhat.com/errata/RHSA-2019:1352
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886

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