CVE-2026-98634 scsi: sd_zbc: Reject disks with too many zones
A malicious SCSI device can cause integer overflows in the Linux kernel's ZBC driver, leading to inconsistent resource allocation and potential denial of service.
- 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-2026-98634?
CVE-2026-98634 is a vulnerability in Linux, published on 18 Oct 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:
scsi: sd_zbc: Reject disks with too many zones
sd_zbc_read_zones() computes the number of zones with 64-bit arithmetic and stores the result in the unsigned int nr_zones field of struct zoned_disk_info, silently truncating counts that exceed 32 bits. The truncated count is later used to size per-zone resources, while the device may still report more zones than fit.
Moreover, sd_zbc_report_zones() counts the reported zones with a signed int zone_idx, which overflows past INT_MAX. Reject devices reporting more than INT_MAX zones at scan time; such a device is not realistic for any medium that exists today, and accepting it produces inconsistent zone bookkeeping.
Which versions are affected by CVE-2026-98634?
How do I fix CVE-2026-98634?
Apply the vendor's patch.
Is CVE-2026-98634 being exploited?
There is no known exploitation of CVE-2026-98634 in the wild and no public exploit code.
Sources
Also known as AZL-109230, BELL-CVE-2026-98634, DEBIAN-CVE-2026-98634, GHSA-gc5v-q6x9-gww4, UBUNTU-CVE-2026-98634.