CVE-2018-18955

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

16/11/2018

Last modified:

24/08/2020

Description

In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.

Impact

Vector 3.x

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.00 HIGH
Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

7.00

Severity 3.x

HIGH

Vector 2.0

AV:L/AC:M/Au:N/C:P/I:P/A:P CVSS v2.0 Severity and Metrics:

Base Score: 4.40 MEDIUM
Vector: AV:L/AC:M/Au:N/C:P/I:P/A:P

Attack Vector (AV): Local
Attack Complexity (AC): Medium
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): Physical
Availability (A): Physical

Base Score 2.0

4.40

Severity 2.0

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:o:linux:linux_kernel::::::::	4.15 (including)	4.19.2 (excluding)
cpe:2.3:o:canonical:ubuntu_linux:16.04::::lts:::
cpe:2.3:o:canonical:ubuntu_linux:18.04::::lts:::
cpe:2.3:o:canonical:ubuntu_linux:18.10:::::::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2018-18955

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools