CVE-2026-68416 mtd: fix double free and WARN_ON in add_mtd_device() error paths
A double free vulnerability in the Linux kernel MTD subsystem allows local attackers to cause a denial of service or potentially execute arbitrary code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68416?
CVE-2026-68416 is an use after free vulnerability in Linux, published on 10 Aug 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:
mtd: fix double free and WARN_ON in add_mtd_device() error paths
When device_register() or mtd_nvmem_add() fails inside add_mtd_device() for a partition, the error handling triggers mtd_release() via put_device() or device_unregister(). mtd_release() calls release_mtd_partition() which frees the mtd_info structure. However, callers such as mtd_add_partition() and add_mtd_partitions() also call free_partition() in their error paths, resulting in a double free.
Additionally, release_mtd_partition() hits WARN_ON(!list_empty( &mtd->part.node)) because the partition node is still linked in the parent's partitions list when the release callback fires from the add_mtd_device() error path.
Fix this by overriding dev->type and dev->release before put_device() in the error paths, so that device_release() invokes a no-op function instead of mtd_release(). For the mtd_nvmem_add() failure case, device_unregister() is replaced with device_del() to separate the device removal from the final kobject reference drop, allowing the override to take effect before put_device() is called.
The callers' error paths (list_del + free_partition) remain the sole owners of mtd_info lifetime on add_mtd_device() failure, which is the expected contract.
The normal partition teardown path is not affected: del_mtd_device() goes through kref_put() -> mtd_device_release() -> device_unregister() with dev->type still set to &mtd_devtype, so mtd_release() -> release_mtd_partition() continues to work correctly for the regular removal case.
Which versions are affected by CVE-2026-68416?
How do I fix CVE-2026-68416?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-68416 being exploited?
There is no known exploitation of CVE-2026-68416 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68416, DEBIAN-CVE-2026-68416, GHSA-qpvq-4872-pr63, UBUNTU-CVE-2026-68416.