Incorrect Authorization Affecting torvalds/linux package, versions [4.15,4.19.2)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
8.98% (93rd percentile)

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  • Snyk IDSNYK-UNMANAGED-TORVALDSLINUX-3005609
  • published26 Jan 2022
  • disclosed16 Nov 2018
  • creditUnknown

Introduced: 16 Nov 2018

CVE-2018-18955  (opens in a new tab)
CWE-863  (opens in a new tab)

How to fix?

Upgrade torvalds/linux to version 4.19.2 or higher.

Overview

Affected versions of this package are vulnerable to Incorrect Authorization. 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.

CVSS Base Scores

version 3.1