{"id":"CVE-2026-93216","state":"PUBLISHED","title":"mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()\n\nprint_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the\nstart to guard against tail pages and NULL data.  However, it later\nre-reads page->memcg_data locklessly in two places:\n\n1: page_memcg_check(page)\n\n2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes\n   VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)\n\nIf the page is concurrently freed and reallocated as a THP tail page or\nslab page between these calls, the VM_BUG_ON assertions can trigger on\nCONFIG_DEBUG_VM=y builds, crashing the kernel.\n\nFix both TOCTOU issues by using the memcg_data snapshot throughout.","publishedAt":"2026-09-24T15:10:38.702Z","updatedAt":"2026-10-21T12:52:21.777Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"e7c1923c5f30a6953f0540e3171d882ec17b05d3","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"a4c940ab3f794f221a338c9431ad1ce0d73a2bea","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"46761406e14381dc35f498c247a87565b87ea2ef","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"90f095b816e25c6a9e4446d299bac5007fdcb3df","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_owner.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_owner.c"]}],"references":["https://git.kernel.org/stable/c/e7c1923c5f30a6953f0540e3171d882ec17b05d3","https://git.kernel.org/stable/c/a4c940ab3f794f221a338c9431ad1ce0d73a2bea","https://git.kernel.org/stable/c/46761406e14381dc35f498c247a87565b87ea2ef","https://git.kernel.org/stable/c/90f095b816e25c6a9e4446d299bac5007fdcb3df"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93216.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93216","state":"PUBLISHED","datePublished":"2026-09-24T15:10:38.702Z","dateUpdated":"2026-10-21T12:52:21.777Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-17T16:02:15.093Z"},"containers":{"cna":{"title":"mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()\n\nprint_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the\nstart to guard against tail pages and NULL data.  However, it later\nre-reads page->memcg_data locklessly in two places:\n\n1: page_memcg_check(page)\n\n2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes\n   VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)\n\nIf the page is concurrently freed and reallocated as a THP tail page or\nslab page between these calls, the VM_BUG_ON assertions can trigger on\nCONFIG_DEBUG_VM=y builds, crashing the kernel.\n\nFix both TOCTOU issues by using the memcg_data snapshot throughout."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"e7c1923c5f30a6953f0540e3171d882ec17b05d3","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"a4c940ab3f794f221a338c9431ad1ce0d73a2bea","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"46761406e14381dc35f498c247a87565b87ea2ef","versionType":"git"},{"version":"fcf8935832b86d3437f00e732c6d0d4d2819d6a9","status":"affected","lessThan":"90f095b816e25c6a9e4446d299bac5007fdcb3df","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_owner.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/page_owner.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e7c1923c5f30a6953f0540e3171d882ec17b05d3"},{"url":"https://git.kernel.org/stable/c/a4c940ab3f794f221a338c9431ad1ce0d73a2bea"},{"url":"https://git.kernel.org/stable/c/46761406e14381dc35f498c247a87565b87ea2ef"},{"url":"https://git.kernel.org/stable/c/90f095b816e25c6a9e4446d299bac5007fdcb3df"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:52:21.777Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}