CVE-2026-43303

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

HIGH
7.8
CVSS Score
Published: May 8, 2026 at 01:11 PM UTC
Updated: October 19, 2026 at 08:18 PM UTC
4 products affected across 2 vendorsLinux KernelSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.18.1 ≤ v < 6.18.166.19 ≤ v < 6.19.63b8000ae185cb068adbda5f966a3835053c85fd45.185.18 rc45.18 rc55.18 rc65.18 rc75.18 rc9
Vendor states this is fixed in 23b82b7a26182ad840ae67d390d7ec9771e8c00f (fixed)
Vendor states this is fixed in 3edb8ebbf79b9016040e8f3421d723ae3d542b32 (fixed)
Vendor states this is fixed in ac1ea219590c09572ed5992dc233bbf7bb70fef9 (fixed)
Vendor states this is fixed in d757c793853ec5483eb41ec2942c300b8fa720fb (fixed)
Vendor states this is fixed in e7790ab165713b79b1617ce659742ceb3a859d05 (fixed)
Vendor states this is fixed in f9719e32a67b4b00b3c9b133e8b5ffa72a26b67b (fixed)
Vendor states this is fixed in 5.18 (unaffected)
Vendor states this is fixed in 6.1.176 (unaffected)
Vendor states this is fixed in 6.12.93 (unaffected)
Vendor states this is fixed in 6.18.16 (unaffected)
Vendor states this is fixed in 6.19.6 (unaffected)
Vendor states this is fixed in 6.6.143 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-416CWE-457

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