CVE-2018-16886
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (4.06%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 4.06% probability · 91th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- etcd/etcd · redhat/enterprise linux desktop · redhat/enterprise linux server · redhat/enterprise linux workstation · fedoraproject/fedora
- Source
- secalert@redhat.com
EPSS 4.1% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/106540Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2019:0237Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:1352Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886Issue Tracking, Patch, Third Party Advisory
- https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authenticationRelease Notes
- https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authenticationRelease Notes
- 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/106540Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2019:0237Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:1352Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886Issue Tracking, Patch, Third Party Advisory
- https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authenticationRelease Notes
- https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authenticationRelease Notes
- 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/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.