High 7.0Published Sep 11, 2025

CVE-2025-39759btrfs: qgroup: fix race between quota disable and quota rescan ioctl

Updated under an hour ago (Oct 28, 2026, 5:50 AM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: btrfs: qgroup: fix race between quota disable and quota rescan ioctl There's a race between a task disabling quotas and another running the rescan ioctl that can result in a use-after-free of qgroup records from the fs_info->qgroup_tree rbtree. This happens as follows: 1) Task A enters btrfs_ioctl_quota_rescan() -> btrfs_qgroup_rescan(); 2) Task B enters btrfs_quota_disable() and calls btrfs_qgroup_wait_for_completion(), which does nothing because at that point fs_info->qgroup_rescan_running is false (it wasn't set yet by task A); 3) Task B calls btrfs_free_qgroup_config() which starts freeing qgroups from fs_info->qgroup_tree without taking the lock fs_info->qgroup_lock; 4) Task A enters qgroup_rescan_zero_tracking() which starts iterating the fs_info->qgroup_tree tree while holding fs_info->qgroup_lock, but task B is freeing qgroup records from that tree without holding the lock, resulting in a use-after-free. Fix this by taking fs_info->qgroup_lock at btrfs_free_qgroup_config(). Also at btrfs_qgroup_rescan() don't start the rescan worker if quotas were already disabled.

CVSS: 7.0 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: May 12, 2026
First seen by InfoSec Signals: Oct 19, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from e685da14af6b31e4b336a110cb1bae1afc268be8 before 7cda0fdde5d9890976861421d207870500f9aace; from e685da14af6b31e4b336a110cb1bae1afc268be8 before b172535ccba12f0cf7d23b3b840989de47fc104d; from e685da14af6b31e4b336a110cb1bae1afc268be8 before dd0b28d877b293b1d7f8727a7de08ae36b6b9ef0; from e685da14af6b31e4b336a110cb1bae1afc268be8 before c38028ce0d0045ca600b6a8345a0ff92bfb47b66; from e685da14af6b31e4b336a110cb1bae1afc268be8 before 2fd0f5ceb997f90f4332ccbab6c7e907e6b2d0eb; from e685da14af6b31e4b336a110cb1bae1afc268be8 before e1249667750399a48cafcf5945761d39fa584edf	CNA record
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name)	before V5.0	CISA ADP
linux linux_kernel linux:linux_kernel	from 3.12 before 6.1.149; from 6.2 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.15.11; from 6.16 before 6.16.2	NVD
debian debian_linux debian:debian_linux	11.0	NVD

References

References

https://git.kernel.org/stable/c/7cda0fdde5d9890976861421d207870500f9aace	patch
https://git.kernel.org/stable/c/b172535ccba12f0cf7d23b3b840989de47fc104d	patch
https://git.kernel.org/stable/c/dd0b28d877b293b1d7f8727a7de08ae36b6b9ef0	patch
https://git.kernel.org/stable/c/c38028ce0d0045ca600b6a8345a0ff92bfb47b66	patch
https://git.kernel.org/stable/c/2fd0f5ceb997f90f4332ccbab6c7e907e6b2d0eb	patch
https://git.kernel.org/stable/c/e1249667750399a48cafcf5945761d39fa584edf	patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	mailing-list, third-party-advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.