CVE-2026-89926 KVM: s390: Fix length check __import_wp_info()
A local attacker can trigger a denial of service in the Linux kernel KVM s390 subsystem by exploiting an integer truncation flaw in length validation.
- 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-2026-89926?
CVE-2026-89926 is a vulnerability in Linux, published on 16 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:
KVM: s390: Fix length check __import_wp_info()
struct kvm_hw_breakpoint::len is a __u64 that is fully controlled by user space. This is then assigned to wp_info->len, which is an int. The bounds check is done on the truncated value while the allocation uses the untruncated one:
wp_info->len = bp_data->len; [...] if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE) return -EINVAL;
wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);
Use the validated value for the allocation as intended. Without this fix userspace can trigger >4GB allocations which will fail and result in a WARN due to MAX_PAGE_ORDER.
Which versions are affected by CVE-2026-89926?
How do I fix CVE-2026-89926?
Apply the vendor's patch.
Is CVE-2026-89926 being exploited?
There is no known exploitation of CVE-2026-89926 in the wild and no public exploit code.
Sources
Also known as AZL-101370, BELL-CVE-2026-89926, DEBIAN-CVE-2026-89926, GHSA-2m53-w88c-rh92, UBUNTU-CVE-2026-89926.