THREATPORT/VULNERABILITY/CVE-2018-18955
HIGH SEVERITY

CVE-2018-18955

Linux Kernel vulnerability

CVSS
7.0
EPSS
7.6%
EPSS pct
94th
Exploited
No known
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.
Affected vendor
Linux
Affected product
Linux Kernel
CVSS vector
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-863 — Incorrect Authorization
Published
2018-11-16

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable with local access, high attack complexity, requiring low privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 7.6% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 94% of all scored CVEs.

Check your external exposure to CVE-2018-18955

  • Confirm whether Linux Linux Kernel is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2018-18955.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2018-18955

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