CVE-2017-12164

Publication date 26 July 2018

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was discovered in gdm 3.24.1 where gdm greeter was no longer setting the ran_once boolean during autologin. If autologin was enabled for a victim, an attacker could simply select 'login as another user' to unlock their screen.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
gdm3	17.10 artful	Fixed 3.26.0-1ubuntu1
	17.04 zesty	Fixed 3.24.1-0ubuntu0.2
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release

Notes

leosilva

according with RHEL it's a side effect introduced in gdm-3.24.1 affecting only artful and zesty.

mdeslaur

introduced by ff98b2817014684ae1acec78ff06f0f461a56a9f

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
gdm3	Upstream: ?id=798

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.4 · Medium

Base metrics

Parameter	Value
Attack vector	Physical
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	6.4 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Other references

https://www.cve.org/CVERecord?id=CVE-2017-12164