CVE-2026-43303 | mm/page_alloc: clear page->private in free_pages_prepare()

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.

Published: 2026-05-08 Last update: 2026-06-19 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-43303 is rated Low Risk (32.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.13%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-43303

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.13% +0.11%
2 2026-05-09 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-43303

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Weakness enumeration for CVE-2026-43303

GitHub Security Advisory for CVE-2026-43303

GHSA-6fh9-96ww-pvwq · Severity: high — In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: clear page-...

OS Trackers for CVE-2026-43303

vendor priority summary link
debian unimportant CVE-2026-43303 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2026-43303
redhat high — https://access.redhat.com/security/cve/CVE-2026-43303
suse medium CVE-2026-43303 severity moderate: SUSE including 18 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 87 product×package rows across 19 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise Live Patching 12 SP5, … (19 product lines)): Known Not Affected 87. https://www.suse.com/security/cve/CVE-2026-43303/
ubuntu medium CVE-2026-43303 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1048, ignored 169, not-affected 89, released 83, needed 55, needs-triage 5. https://ubuntu.com/security/CVE-2026-43303

Affected software / configurations for CVE-2026-43303

Vendor Product Version Raw CPE
linux linux_kernel >= 5.18, < 6.1.176 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.18, < 6.6.143 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.18, < 6.12.93 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.18, < 6.18.16 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.18, < 6.19.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.18, < 7.0 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References for CVE-2026-43303

cvelogic Threat Intelligence