CVE intelligence and bounded remediation

CVE-2018-13405 — Linux Linux Kernel security vulnerability

High CVSS 7.8

The inode_init_owner function in fs/inode.c in the Linux kernel through 3.16 allows local users to create files with an unintended group ownership, in a scenario where a directory is SGID to a certain group and is writable by a user who is not a member of that group. Here, the non-member can trigger creation of a plain file whose group ownership is that group. The intended behavior was that the non-member can trigger creation of a directory (but not a plain file) whose group ownership is that group. The non-member can escalate privileges by making the plain file executable and SGID.

Severity
High
CVSS
7.8 (3.1)
Published
2018-07-06
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-269

Affected products

  • linux / linux_kernel
  • debian / debian_linux / 8.0
  • debian / debian_linux / 9.0
  • canonical / ubuntu_linux / 14.04
  • canonical / ubuntu_linux / 16.04
  • canonical / ubuntu_linux / 18.04

Showing 6 representative product identities from 92 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Privilege escalation and unsafe privilege management

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
  • Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
  • Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

  • Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
  • Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
  • Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.

Authoritative sources

Complete CVE record and remediation plan

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