CVE-2026-89926

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References