In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix race between quota enable and quota rescan ioctl
When enabling quotas, at btrfs_quota_enable(), after committing the transaction, we change fs_info->quota_root to point to the quota root we created and set BTRFS_FS_QUOTA_ENABLED at fs_info->flags. Then we try to start the qgroup rescan worker, first by initializing it with a call to qgroup_rescan_init() - however if that fails we end up freeing the quota root but we leave fs_info->quota_root still pointing to it, this can later result in a use-after-free somewhere else.
We have previously set the flags BTRFS_FS_QUOTA_ENABLED and BTRFS_QGROUP_STATUS_FLAG_ON, so we can only fail with -EINPROGRESS at btrfs_quota_enable(), which is possible if someone already called the quota rescan ioctl, and therefore started the rescan worker.
So fix this by ignoring an -EINPROGRESS and asserting we can't get any other error.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | - | 4.19.262 |
| linux / linux_kernel | 4.20 | 5.4.220 |
| linux / linux_kernel | 5.5 | 5.10.150 |
| linux / linux_kernel | 5.11 | 5.15.75 |
| linux / linux_kernel | 5.16 | 5.19.17 |
| linux / linux_kernel | 6.0 | 6.0.3 |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
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