Auth bypass in Linux Kernel
CVE-2018-18397
The userfaultfd implementation in the Linux kernel before 4.19.7 mishandles access control for certain UFFDIO_ ioctl calls, as demonstrated by allowing local users to write data into holes in a tmpfs file (if the user has read-only access to that file, and that file contains holes), related to fs/userfaultfd.c and mm/userfaultfd.c.
Vulnerability class: Broken Access Control
EPSS: 0.005 (40.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Linux Linux_kernel
- Canonical Ubuntu_linux — versions 14.04, 16.04, 18.04
- Redhat Enterprise_linux_desktop — versions 7.0
- Redhat Enterprise_linux_server — versions 7.0
- Redhat Enterprise_linux_server_aus — versions 7.4, 7.6
- Redhat Enterprise_linux_server_eus — versions 7.4, 7.5, 7.6
- Redhat Enterprise_linux_server_tus — versions 7.4, 7.6
- Redhat Enterprise_linux_workstation — versions 7.0
- Redhat Openshift_container_platform — versions 3.11
- Redhat Virtualization_host — versions 4.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- cve@mitre.org (Patch, x_refsource_MISC, Vendor Advisory)
- cve@mitre.org (Patch, Third Party Advisory, x_refsource_MISC)
- cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- cve@mitre.org (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)
- cve@mitre.org (Exploit, Third Party Advisory, x_refsource_MISC, Issue Tracking)
- cve@mitre.org (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)
- cve@mitre.org (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)
- cve@mitre.org (Patch, Third Party Advisory, x_refsource_MISC)
- cve@mitre.org (Patch, x_refsource_MISC, Vendor Advisory)
Frequently asked questions
- What is CVE-2018-18397?
- CVE-2018-18397 is a medium-severity vulnerability in Linux Kernel, classified under Incorrect Authorization. CVSS score: 5.5/10. Published 2018-12-12.
- How severe is CVE-2018-18397?
- Medium severity. CVSS v3 base score is 5.5 out of 10.
- Is CVE-2018-18397 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.