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.
Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-3832-1 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-3833-1 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-3835-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-3836-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-3836-2 Linux kernel (HWE) vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

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Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2024-08-05T11:23:08.917Z

Reserved: 2018-11-05T00:00:00

Link: CVE-2018-18955

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2018-11-16T20:29:00.233

Modified: 2024-11-21T03:56:56.423

Link: CVE-2018-18955

cve-icon Redhat

Severity : Important

Publid Date: 2018-11-15T00:00:00Z

Links: CVE-2018-18955 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses