{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64130","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.036Z","datePublished":"2026-07-19T15:40:26.108Z","dateUpdated":"2026-07-19T15:40:26.108Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-07-19T15:40:26.108Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free\n\n__GFP_ZEROTAGS semantics are currently a bit weird, but effectively this\nflag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN.\n\nIf we run with init_on_free, we will zero out pages during\n__free_pages_prepare(), to skip zeroing on the allocation path.\n\nHowever, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will\nconsequently not only skip clearing page content, but also skip clearing\ntag memory.\n\nNot clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that\nwill get mapped to user space through set_pte_at() later: set_pte_at() and\nfriends will detect that the tags have not been initialized yet\n(PG_mte_tagged not set), and initialize them.\n\nHowever, for the huge zero folio, which will be mapped through a PMD\nmarked as special, this initialization will not be performed, ending up\nexposing whatever tags were still set for the pages.\n\nThe docs (Documentation/arch/arm64/memory-tagging-extension.rst) state\nthat allocation tags are set to 0 when a page is first mapped to user\nspace.  That no longer holds with the huge zero folio when init_on_free is\nenabled.\n\nFix it by decoupling __GFP_ZEROTAGS from __GFP_ZERO, passing to\ntag_clear_highpages() whether we want to also clear page content.\n\nInvert the meaning of the tag_clear_highpages() return value to have\nclearer semantics.\n\nReproduced with the huge zero folio by modifying the check_buffer_fill\narm64/mte selftest to use a 2 MiB area, after making sure that pages have\na non-0 tag set when freeing (note that, during boot, we will not actually\ninitialize tags, but only set KASAN_TAG_KERNEL in the page flags).\n\n\t$ ./check_buffer_fill\n\t1..20\n\t...\n\tnot ok 17 Check initial tags with private mapping, sync error mode and mmap memory\n\tnot ok 18 Check initial tags with private mapping, sync error mode and mmap/mprotect memory\n\t...\n\nThis code needs more cleanups; we'll tackle that next, like\ndecoupling __GFP_ZEROTAGS from __GFP_SKIP_KASAN.\n\n[akpm@linux-foundation.org: s/__GPF_ZERO/__GFP_ZERO/, per David]"}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/page.h","arch/arm64/mm/fault.c","include/linux/gfp_types.h","include/linux/highmem.h","mm/page_alloc.c"],"versions":[{"version":"adfb6609c6809e107ded9a1cd46f519c882e64ea","lessThan":"738d18f1da3513d17b6f7bf30146cc4ac2480ffd","status":"affected","versionType":"git"},{"version":"adfb6609c6809e107ded9a1cd46f519c882e64ea","lessThan":"2f2aec5120b93a8f8b52dc50cdc60dbb8aec72f6","status":"affected","versionType":"git"},{"version":"adfb6609c6809e107ded9a1cd46f519c882e64ea","lessThan":"6a288a4ddb4a994490505ab5f41c445f8e6b6467","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/page.h","arch/arm64/mm/fault.c","include/linux/gfp_types.h","include/linux/highmem.h","mm/page_alloc.c"],"versions":[{"version":"6.18","status":"affected"},{"version":"0","lessThan":"6.18","status":"unaffected","versionType":"semver"},{"version":"6.18.34","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/738d18f1da3513d17b6f7bf30146cc4ac2480ffd"},{"url":"https://git.kernel.org/stable/c/2f2aec5120b93a8f8b52dc50cdc60dbb8aec72f6"},{"url":"https://git.kernel.org/stable/c/6a288a4ddb4a994490505ab5f41c445f8e6b6467"}],"title":"mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free","x_generator":{"engine":"bippy-1.2.0"}}}}