CVE-2018-18955
HIGH 7.0EPSS 7.6%
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.
- CVSS v3.0 NVD
- 7.0 HIGH
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS v2.0 NVD
- 4.4 MEDIUM
AV:L/AC:M/Au:N/C:P/I:P/A:P - EPSS
- 7.61% chance of exploitation in the next 30 days, 94th percentile
- Published
- 2018-11-16
- Updated
- 2024-08-05
Proof-of-concept exploits (3)
- HaleyWei/POC-available2★ · 2020-09-21
- scheatkode/CVE-2018-1895525★ · 2022-01-20
- WhatsWrongAndWhy/CVE-2018-189550★ · 2026-07-21
Metasploit modules (1)
ExploitDB entries (6)
- https://www.exploit-db.com/exploits/45915
- https://www.exploit-db.com/exploits/45886
- https://www.exploit-db.com/exploits/47167
- https://www.exploit-db.com/exploits/47166
- https://www.exploit-db.com/exploits/47165
- https://www.exploit-db.com/exploits/47164
Security advisories
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c95…
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2
- torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
- http://www.securityfocus.com/bid/105941
- https://bugs.chromium.org/p/project-zero/issues/detail?id=1712
- https://usn.ubuntu.com/3832-1
- https://usn.ubuntu.com/3833-1
- https://usn.ubuntu.com/3835-1
- https://usn.ubuntu.com/3836-1
- https://usn.ubuntu.com/3836-2