Bug 2535186 (CVE-2026-89926) - CVE-2026-89926 kernel: KVM: s390: Fix length check __import_wp_info()
Summary: CVE-2026-89926 kernel: KVM: s390: Fix length check __import_wp_info()
Keywords:
Status: NEW
Alias: CVE-2026-89926
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 11:16 UTC by OSIDB Bzimport
Modified: 2026-10-20 13:07 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-09-16 11:16:53 UTC
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.


Note You need to log in before you can comment on or make changes to this bug.