CVE-2018-18955
7.0
HIGH
CVSS 3.1
EPSS 7.6%
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.
How to fix CVE-2018-18955
To remediate CVE-2018-18955, upgrade the affected package to a fixed version below.
- —upgrade to 4.18.20-1 or later
Is CVE-2018-18955 being exploited?
Moderate — EPSS is 7.6%. Track this CVE but it's not at the top of the prioritisation list.
Affected packages (1)
- from 0, < 4.18.20-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.0 | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |