CVE-2018-16886

Publication date 14 January 2019

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
etcd	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Ignored end of life
	18.10 cosmic	Ignored end of life
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release

Notes

msalvatore

Introduced by https://github.com/etcd-io/etcd/commit/0191509637546621d6f2e18e074e955ab8ef374d

Severity score breakdown

Parameter	Value
Base score	6.8 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	None
Vector	CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N