CVE-2026-93827

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

virtio-fs: avoid double-free on failed queue setup

virtio_fs_setup_vqs() allocates fs->vqs and fs->mq_map before calling virtio_find_vqs(). If virtio_find_vqs() fails, the error path frees both pointers and returns an error to virtio_fs_probe().

virtio_fs_probe() then drops the last kobject reference, and virtio_fs_ktype_release() frees fs->vqs and fs->mq_map again. This leaves dangling pointers in struct virtio_fs and can trigger a double-free during probe failure cleanup.

Set fs->vqs and fs->mq_map to NULL immediately after kfree() in the virtio_fs_setup_vqs() error path so that the later kobject release sees an uninitialized state and kfree(NULL) becomes harmless.

This can be reproduced when a broken virtio-fs device advertises more request queues than the transport actually provides. In that case virtio_find_vqs() fails while setting up the extra queue, and the probe path reaches the double-free cleanup sequence.

Affected product:

AlmaLinux 9.2 ESU , Debian 10 ELS , Debian 11 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

linux @ 5.10.259 (+7 more)

Live-patch status from KernelCare for each operating system.