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

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-28 · updated 2026-06-24
Weakness: CWE-415

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.

Affected products

Linux kernel: from 6.1.162 before 6.1.175; from 6.6.122 before 6.6.140; from 6.12.67 before 6.12.88; from 6.18.7 before 6.18.30; from 6.19.1 before 7.0.7; 6.19, 6.19-rc6, 6.19-rc7, 6.19-rc8 — fixed in 6.1.175, 6.12.88, 6.18.30, 6.6.140, 7.0.7

How to fix

Upgrade to a fixed version: Linux kernel 6.1.175, 6.12.88, 6.18.30, 6.6.140. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-46129 or the next vulnerability affects your stack