# CVE-2026-46129: btrfs: fix double free in create_space_info() error path

> A double free vulnerability in the Linux kernel's btrfs filesystem allows attackers to potentially execute arbitrary code or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-89088, BELL-CVE-2026-46129, DEBIAN-CVE-2026-46129, GHSA-4m7v-4fw7-9hch, ROOT-OS-DEBIAN-12-CVE-2026-46129, ROOT-OS-UBUNTU-2404-CVE-2026-46129, UBUNTU-CVE-2026-46129

## What is CVE-2026-46129?

CVE-2026-46129 is a high-severity use after free vulnerability in Linux kernel, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix double free in create_space_info() error path

When kobject_init_and_add() fails, the call chain is:

create_space_info()
-> btrfs_sysfs_add_space_info_type()
-> kobject_init_and_add()
-> failure
-> kobject_put(&space_info->kobj)
-> space_info_release()
-> kfree(space_info)

Then control returns to create_space_info():

btrfs_sysfs_add_space_info_type() returns error
-> goto out_free
-> kfree(space_info)

This causes a double free.

Keep the direct kfree(space_info) for the earlier failure path, but
after btrfs_sysfs_add_space_info_type() has called kobject_put(), let
the kobject release callback handle the cleanup.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-46129?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46129?

Apply the vendor's patch.

## Is CVE-2026-46129 being exploited?

There is no known exploitation of CVE-2026-46129 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46129 and fix it if it is affected.

What it is: CVE-2026-46129 is a high-severity use after free vulnerability in Linux kernel, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-46129 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-46129/ (Markdown: https://insights.sbomify.com/CVE-2026-46129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46129
- OSV: https://osv.dev/vulnerability/CVE-2026-46129

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46129/
Summaries are generated and may contain mistakes; the official description above is the record.