CVE-2026-74481
Received Received - Intake

BaseFortify

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: mm/page_reporting: use system_freezable_wq to fix UAF during suspend During PM freeze (e.g. S3 suspend or S4 hibernation), device drivers like virtio_balloon reset their underlying virtio devices and delete their virtqueues via vdev->config->del_vqs(). However, page reporting work (page_reporting_process) was scheduled on the global system_wq. Because system_wq lacks the WQ_FREEZABLE flag, the PM freezer skips it, leaving page_reporting_process active during suspend. If pages are freed into the buddy allocator while suspending (for example, when core MM invokes the balloon shrinker during S4 hibernation image saving), page reporting triggers virtballoon_free_page_report() on deleted virtqueues, resulting in a Use-After-Free / General Protection Fault: [ 196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI [ 196.825967] Workqueue: events page_reporting_process [ 196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring] [ 196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon] [ 196.946943] page_reporting_process+0x370/0x4f0 Fix this by switching page reporting work to system_freezable_wq. This ensures that the PM freezer pauses page_reporting_process before device drivers destroy their reporting virtqueues. Because the reporting worker is frozen, memory reclamation/freeing (e.g. via shrinker execution) can safely return pages to MM during freeze without triggering unfrozen reporting work on deleted virtqueues. This aligns with the driver's existing design. The comment in virtballoon_freeze() states: /* * The workqueue is already frozen by the PM core before this * function is called. */ Testing: I have verified these fixes using Google’s virtualization infrastructure by running continuous suspend/resume iterations (40+ cycles) while churning memory using stress-ng (`stress-ng --vm 4 --vm-bytes 60% --timeout 1`) to constantly create free pages for the buddy allocator. We also set the `page_reporting_order` parameter to 0 to make the page reporting worker highly sensitive, forcing it to pick up any 4K free pages. This confirmed that the UAF crashes are no longer reproducible.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
CVE-2026-74481
EUVD
EUVD-2026-59674

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a Use-After-Free (UAF) vulnerability in the Linux kernel during system suspend operations. When the system enters suspend mode (like S3 or S4), device drivers reset their virtio devices and delete virtqueues. However, page reporting work was scheduled on a non-freezable workqueue, causing it to remain active during suspend. If memory pages are freed during suspend, page reporting may access deleted virtqueues, leading to a general protection fault.

Detection Guidance

This vulnerability is specific to the Linux kernel and may not have direct network detection methods. Monitor kernel logs for general protection faults or crashes during suspend/resume cycles, particularly involving virtio_balloon or page_reporting_process. Check for errors like 'general protection fault' in dmesg or /var/log/kern.log.

Impact Analysis

This vulnerability can cause system crashes or instability during suspend/resume cycles, particularly on systems using virtio_balloon for memory management. It may lead to kernel panics or unexpected reboots when memory is freed during suspend operations.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for this vulnerability. If updating is not immediately possible, consider disabling the virtio-balloon driver or page reporting features as a temporary workaround.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-74481. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart