Public exploit available
Public proof-of-concept or exploit code exists (ExploitDB / Metasploit / Nuclei).

CVE-2018-18955Incorrect Authorization in Kernel

Severity
7.0HIGHNVD
EPSS
9.6%
top 7.12%
CISA KEV
Not in KEV
Exploit
PoC available
Public exploit / PoC exists
Timeline
PublishedNov 16
Latest updateMay 13

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-namesp

CVSS vector

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitability: 1.0 | Impact: 5.9

Affected Packages4 packages

NVDlinux/linux_kernel4.154.19.2
Debianlinux/linux_kernel< 4.18.20-1+3
Ubuntulinux/linux_kernel< 4.15.0-42.45
debiandebian/linux< linux 4.18.20-1 (bookworm)

Also affects: Ubuntu Linux 16.04, 18.04, 18.10

Patches

🔴Vulnerability Details

6
GHSA
GHSA-c6xj-3c77-g5rg: In the Linux kernel 42022-05-13
OSV
linux-hwe, linux-gcp vulnerabilities2018-12-04
OSV
linux, linux-gcp, linux-kvm, linux-raspi2 vulnerabilities2018-12-03
OSV
linux-aws vulnerabilities2018-11-30
OSV
CVE-2018-18955: In the Linux kernel 42018-11-16

💥Exploits & PoCs

7
Exploit-DB
Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (polkit Method)2019-01-04
Exploit-DB
Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (dbus Method)2019-01-04
Exploit-DB
Linux - Nested User Namespace idmap Limit Local Privilege Escalation (Metasploit)2018-11-29
Exploit-DB
Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (ldpreload Method)2018-11-21
Exploit-DB
Linux Kernel 4.15.x < 4.19.2 - 'map_write() CAP_SYS_ADMIN' Local Privilege Escalation (cron Method)2018-11-21

📋Vendor Advisories

7
Ubuntu
Linux kernel (HWE) vulnerabilities2018-12-04
Ubuntu
Linux kernel vulnerabilities2018-12-03
Ubuntu
Linux kernel vulnerabilities2018-12-03
Ubuntu
Linux kernel (AWS) vulnerabilities2018-11-30
Ubuntu
Linux kernel (AWS) vulnerabilities2018-11-30

📄Research Papers

1
arXiv
The Ideal Versus the Real: Revisiting the History of Virtual Machines and Containers2019-04-27

💬Community

2
Bugzilla
CVE-2018-18955 kernel: Privilege escalation in map_write() in kernel/user_namespace.c [fedora-all]2018-11-22
Bugzilla
CVE-2018-18955 kernel: Privilege escalation in map_write() in kernel/user_namespace.c2018-11-19