CVE-2026-98635 scsi: block: Fix zones_cond out-of-bounds write on zone report
A malicious SCSI device can trigger an out-of-bounds write in the Linux kernel, potentially leading to code execution or system crash.
- 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-2026-98635?
CVE-2026-98635 is a memory corruption 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: block: Fix zones_cond out-of-bounds write on zone report
blk_revalidate_disk_zones() sizes the zones_cond array from the disk capacity and zone size, but the index used by blk_revalidate_zone_cond() comes from the device-driven report_zones() walk and is never checked against the array size. A device reporting more zones than fit the array makes blk_zone_set_cond() write out of bounds.
One way to reach this is a zone count exceeding 32 bits: both blk_revalidate_zone_args.nr_zones and struct zoned_disk_info.nr_zones are unsigned int, so a disk advertising more than UINT_MAX zones (e.g. 2^32 + 1024 zones of one 512-byte logical block) gets its zone count truncated to a small value, undersizing the array while the report walk keeps counting upward.
Check the index against the array size before storing the zone condition, and refuse to revalidate when the zone count does not fit 32 bits.
Which versions are affected by CVE-2026-98635?
How do I fix CVE-2026-98635?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98635 being exploited?
There is no known exploitation of CVE-2026-98635 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-98635, GHSA-xmm2-hmmq-mgf4, UBUNTU-CVE-2026-98635.