{"id":"CVE-2026-43303","state":"PUBLISHED","title":"mm/page_alloc: clear page->private in free_pages_prepare()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: clear page->private in free_pages_prepare()\n\nSeveral subsystems (slub, shmem, ttm, etc.) use page->private but don't\nclear it before freeing pages.  When these pages are later allocated as\nhigh-order pages and split via split_page(), tail pages retain stale\npage->private values.\n\nThis causes a use-after-free in the swap subsystem.  The swap code uses\npage->private to track swap count continuations, assuming freshly\nallocated pages have page->private == 0.  When stale values are present,\nswap_count_continued() incorrectly assumes the continuation list is valid\nand iterates over uninitialized page->lru containing LIST_POISON values,\ncausing a crash:\n\n  KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]\n  RIP: 0010:__do_sys_swapoff+0x1151/0x1860\n\nFix this by clearing page->private in free_pages_prepare(), ensuring all\nfreed pages have clean state regardless of previous use.","publishedAt":"2026-05-08T13:11:23.561Z","updatedAt":"2026-10-19T19:16:26.022Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"e7790ab165713b79b1617ce659742ceb3a859d05","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"3edb8ebbf79b9016040e8f3421d723ae3d542b32","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"f9719e32a67b4b00b3c9b133e8b5ffa72a26b67b","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"23b82b7a26182ad840ae67d390d7ec9771e8c00f","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"d757c793853ec5483eb41ec2942c300b8fa720fb","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"ac1ea219590c09572ed5992dc233bbf7bb70fef9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_alloc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.16","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.6","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_alloc.c"]}],"references":["https://git.kernel.org/stable/c/e7790ab165713b79b1617ce659742ceb3a859d05","https://git.kernel.org/stable/c/3edb8ebbf79b9016040e8f3421d723ae3d542b32","https://git.kernel.org/stable/c/f9719e32a67b4b00b3c9b133e8b5ffa72a26b67b","https://git.kernel.org/stable/c/23b82b7a26182ad840ae67d390d7ec9771e8c00f","https://git.kernel.org/stable/c/d757c793853ec5483eb41ec2942c300b8fa720fb","https://git.kernel.org/stable/c/ac1ea219590c09572ed5992dc233bbf7bb70fef9","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":["CWE-457"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43303.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43303","state":"PUBLISHED","datePublished":"2026-05-08T13:11:23.561Z","dateUpdated":"2026-10-19T19:16:26.022Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:56.000Z"},"containers":{"cna":{"title":"mm/page_alloc: clear page->private in free_pages_prepare()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: clear page->private in free_pages_prepare()\n\nSeveral subsystems (slub, shmem, ttm, etc.) use page->private but don't\nclear it before freeing pages.  When these pages are later allocated as\nhigh-order pages and split via split_page(), tail pages retain stale\npage->private values.\n\nThis causes a use-after-free in the swap subsystem.  The swap code uses\npage->private to track swap count continuations, assuming freshly\nallocated pages have page->private == 0.  When stale values are present,\nswap_count_continued() incorrectly assumes the continuation list is valid\nand iterates over uninitialized page->lru containing LIST_POISON values,\ncausing a crash:\n\n  KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]\n  RIP: 0010:__do_sys_swapoff+0x1151/0x1860\n\nFix this by clearing page->private in free_pages_prepare(), ensuring all\nfreed pages have clean state regardless of previous use."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"e7790ab165713b79b1617ce659742ceb3a859d05","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"3edb8ebbf79b9016040e8f3421d723ae3d542b32","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"f9719e32a67b4b00b3c9b133e8b5ffa72a26b67b","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"23b82b7a26182ad840ae67d390d7ec9771e8c00f","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"d757c793853ec5483eb41ec2942c300b8fa720fb","versionType":"git"},{"version":"3b8000ae185cb068adbda5f966a3835053c85fd4","status":"affected","lessThan":"ac1ea219590c09572ed5992dc233bbf7bb70fef9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_alloc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.93","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.16","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.6","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_alloc.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e7790ab165713b79b1617ce659742ceb3a859d05"},{"url":"https://git.kernel.org/stable/c/3edb8ebbf79b9016040e8f3421d723ae3d542b32"},{"url":"https://git.kernel.org/stable/c/f9719e32a67b4b00b3c9b133e8b5ffa72a26b67b"},{"url":"https://git.kernel.org/stable/c/23b82b7a26182ad840ae67d390d7ec9771e8c00f"},{"url":"https://git.kernel.org/stable/c/d757c793853ec5483eb41ec2942c300b8fa720fb"},{"url":"https://git.kernel.org/stable/c/ac1ea219590c09572ed5992dc233bbf7bb70fef9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable swap continuation and page allocator paths are reached through local memory-management activity such as fork/swap/reclaim or swap administration, not by remote packets or physical access.\nAC:L - There is no attacker-uncontrolled race; a local attacker can repeatedly create swap pressure and duplicate swapped entries to drive the continuation path, and allocator grooming is under attacker influence.\nPR:L - Although swapon/swapoff require CAP_SYS_ADMIN in init_user_ns, the same vulnerable swap_count_continued() path is reachable by an unprivileged local user through normal swapped PTE duplication paths once swap is active.\nUI:N - No victim action is required after the attacker has local execution; the trigger can be driven by the attacker's own processes and memory activity.\nS:U - The impact remains within the kernel and the same host security authority; this is not a VM escape or cross-boundary IOMMU/DMA issue.\nC:H - The stale page->private value causes a use-after-free style interpretation of stale struct page list metadata, leading to wild kernel memory accesses that can plausibly be shaped into information disclosure.\nI:H - swap_count_continued() can write through a page derived from stale list pointers, making this kernel memory corruption with plausible arbitrary write/control-flow impact.\nA:H - The reported failure is a KASAN wild-memory-access crash in __do_sys_swapoff, and the same invalid list traversal can oops or panic the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:27:08.856Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.18.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.19.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - 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