CVE-2026-74472 ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()
A local attacker can trigger a kernel crash or leak process information by manipulating ublk device state fields during device addition.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74472?
CVE-2026-74472 is a vulnerability in Linux, published on 15 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:
ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()
ublk_ctrl_add_dev() memcpy()s the userspace ublksrv_ctrl_dev_info into ub->dev_info and then fixes up the fields the driver owns, but misses ->state and ->ublksrv_pid.
A device added with ->state = UBLK_S_DEV_LIVE passes the "->state != UBLK_S_DEV_DEAD" test that ublk_stop_dev_unlocked() uses as its proxy for "a disk is attached", while ->ub_disk is still NULL, so DEL_DEV right after ADD_DEV oopses in del_gendisk(). UBLK_S_DEV_QUIESCED plus UBLK_F_USER_RECOVERY dies one step earlier, in ublk_force_abort_dev(). A poisoned ->state also gets START_USER_RECOVERY and the char device read/write path onto a device that was never started, and wedges START_DEV at -EEXIST. A poisoned ->ublksrv_pid just makes GET_DEV_INFO report an unrelated task as the ublk server.
Reset both after the memcpy(), as ublk_detach_disk() does. Userspace only ever reads these back, so correcting them silently breaks nothing.
ADD_DEV has copied ->state in unsanitized since ublk was merged, but back then it was harmless: the gendisk was allocated during ADD_DEV, and both teardown and the START_DEV -EEXIST check keyed off disk_live() rather than ->state. The oops became reachable once the disk allocation moved to START_DEV and those checks switched to ->state.
Which versions are affected by CVE-2026-74472?
How do I fix CVE-2026-74472?
Apply the vendor's patch.
Is CVE-2026-74472 being exploited?
There is no known exploitation of CVE-2026-74472 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74472, DEBIAN-CVE-2026-74472, GHSA-7jg9-vhj9-wg56, UBUNTU-CVE-2026-74472.