Bug 2468091 (CVE-2026-43303) - CVE-2026-43303 kernel: mm/page_alloc: clear page->private in free_pages_prepare()
Summary: CVE-2026-43303 kernel: mm/page_alloc: clear page->private in free_pages_prepa...
Keywords:
Status: NEW
Alias: CVE-2026-43303
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-08 14:04 UTC by OSIDB Bzimport
Modified: 2026-06-29 19:23 UTC (History)
2 users (show)

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


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:21556 0 None None None 2026-05-28 01:24:12 UTC
Red Hat Product Errata RHSA-2026:21557 0 None None None 2026-05-28 01:20:08 UTC
Red Hat Product Errata RHSA-2026:26462 0 None None None 2026-06-17 01:14:04 UTC
Red Hat Product Errata RHSA-2026:26515 0 None None None 2026-06-17 06:33:39 UTC
Red Hat Product Errata RHSA-2026:27708 0 None None None 2026-06-22 05:56:02 UTC
Red Hat Product Errata RHSA-2026:27735 0 None None None 2026-06-22 06:02:10 UTC
Red Hat Product Errata RHSA-2026:33215 0 None None None 2026-06-29 19:23:57 UTC

Description OSIDB Bzimport 2026-05-08 14:04:02 UTC
In the Linux kernel, the following vulnerability has been resolved:

mm/page_alloc: clear page->private in free_pages_prepare()

Several subsystems (slub, shmem, ttm, etc.) use page->private but don't
clear it before freeing pages.  When these pages are later allocated as
high-order pages and split via split_page(), tail pages retain stale
page->private values.

This causes a use-after-free in the swap subsystem.  The swap code uses
page->private to track swap count continuations, assuming freshly
allocated pages have page->private == 0.  When stale values are present,
swap_count_continued() incorrectly assumes the continuation list is valid
and iterates over uninitialized page->lru containing LIST_POISON values,
causing a crash:

  KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]
  RIP: 0010:__do_sys_swapoff+0x1151/0x1860

Fix this by clearing page->private in free_pages_prepare(), ensuring all
freed pages have clean state regardless of previous use.

Comment 5 errata-xmlrpc 2026-05-28 01:20:07 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:21557 https://access.redhat.com/errata/RHSA-2026:21557

Comment 6 errata-xmlrpc 2026-05-28 01:24:11 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:21556 https://access.redhat.com/errata/RHSA-2026:21556

Comment 7 errata-xmlrpc 2026-06-17 01:14:03 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:26462 https://access.redhat.com/errata/RHSA-2026:26462

Comment 8 errata-xmlrpc 2026-06-17 06:33:38 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:26515 https://access.redhat.com/errata/RHSA-2026:26515

Comment 10 errata-xmlrpc 2026-06-22 05:56:01 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:27708 https://access.redhat.com/errata/RHSA-2026:27708

Comment 11 errata-xmlrpc 2026-06-22 06:02:09 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:27735 https://access.redhat.com/errata/RHSA-2026:27735

Comment 12 errata-xmlrpc 2026-06-29 19:23:56 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:33215 https://access.redhat.com/errata/RHSA-2026:33215


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