CVE-2026-74722: btrfs: fix memory leak in btrfs_do_encoded_write()
btrfs: fix memory leak in btrfsdoencodedwrite()
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.152.1-1 - Upgrade
Upgrade
linux kernelto a version that resolves this vulnerability.Fixed in 6.12.94 - Compensating control
If you run an affected btrfs kernel, consider limiting exposure to ioctls that can trigger btrfs_do_encoded_write memory leak until fixed kernels are deployed.
Event History
Frequently Asked Questions
What systems are exposed to this leak?
Systems using the Linux kernel with Btrfs are relevant. The reported path is the Btrfs encoded-write ioctl, and the leak occurs while reserving qgroup data during that operation.
What does an attacker or triggering process need to do?
The issue is triggered through an encoded write issued via the Btrfs ioctl interface. The report shows it was found through local fuzzing, so local access to perform operations against a Btrfs filesystem is implicated.
How can I determine whether the issue is occurring on a system?
The report identifies the leak through kmemleak and shows an allocation originating in extent_changeset_alloc, called from qgroup_reserve_data during btrfs_do_encoded_write. Inspecting kmemleak reports for this call chain can indicate that the leak has been triggered.