CVE-2018-18955

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.

Weakness classification

• CWE-863: Incorrect Authorization

Primary references

• cve@mitre.org — Patch, Vendor Advisory
• cve@mitre.org — Third Party Advisory, VDB Entry
• cve@mitre.org — Patch, Third Party Advisory
• cve@mitre.org — Patch, Vendor Advisory
• cve@mitre.org — Patch, Vendor Advisory
• cve@mitre.org — Patch, Vendor Advisory
• cve@mitre.org
• cve@mitre.org
• cve@mitre.org — Third Party Advisory
• cve@mitre.org — Third Party Advisory
• cve@mitre.org — Third Party Advisory
• cve@mitre.org — Third Party Advisory