CVE-2026-93049 mtd: mtdswap: Avoid freeing registered blktrans device twice
A double-free vulnerability in the Linux kernel's mtdswap driver 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-2026-93049?
CVE-2026-93049 is an use after free vulnerability in Linux, published on 17 Sep 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: mtdswap: Avoid freeing registered blktrans device twice
In mtdswap_add_mtd(), debugfs setup failure after successful blktrans registration can free mbd_dev twice.
add_mtd_blktrans_dev() initializes the blktrans device reference and publishes the disk. Once that succeeds, del_mtd_blktrans_dev() tears the disk down and drops the blktrans reference; when that reference reaches zero, blktrans_dev_release() frees the mtd_blktrans_dev.
The debugfs failure path called del_mtd_blktrans_dev(mbd_dev), then fell through the common cleanup label and called kfree(mbd_dev) again. Clear the local pointer after deregistration so the common cleanup can still release the mtdswap state without freeing the blktrans object twice.
This issue was found by a static analysis checker and confirmed by manual source review.
Which versions are affected by CVE-2026-93049?
How do I fix CVE-2026-93049?
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-2026-93049 being exploited?
There is no known exploitation of CVE-2026-93049 in the wild and no public exploit code.
Sources
Also known as AZL-102629, BELL-CVE-2026-93049, DEBIAN-CVE-2026-93049, GHSA-vm56-mgvf-744c, UBUNTU-CVE-2026-93049.