{"id":"CVE-2026-68172","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-68172","summary":"arm64: make huge_ptep_get handled unaligned addresses","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: make huge_ptep_get handled unaligned addresses\n\nhuge_ptep_get() can be handed a virtual address pointing to the middle\nof a contpmd/contpte mapped hugetlb folio (examples of callers are\npagemap_hugetlb_range, page_mapped_in_vma).\n\nThe arm64 helper rewalks the pgtables in find_num_contig to answer\nwhether the huge pte we have maps a contpmd or a contpte hugetlb folio,\nand returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over\nthe contiguous ptes. We can falsely return CONT_PTES instead of\nCONT_PMDS if the addr is not aligned. On systems where CONT_PTES !=\nCONT_PMDS (meaning page size is 16K), we could collect excess A/D bit\nstate, meaning extra work for the kernel. Even worse, we may iterate\nbeyond the PTE table and dereference a garbage ptep pointer to access\nphysical memory we don't own. Since the ptep pointer is a linear map\naddress, we may run off the end of the linear map or into a hole,\ndereference a VA not mapped into the kernel pgtables and cause kernel\npanic.\n\nFix this by aligning the pmdp pointer down to a contpmd base before\nchecking equality with the passed huge pte pointer, to correctly answer\nwhether the huge pte is the base of a contpmd block.","published":"2026-08-10T11:59:41.893Z","modified":"2026-08-14T04:03:55.691945245Z","cvss":{"score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.42"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/9cd4b1a52eff330798d668c1775f8bc450776280"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f3530aec26563f4d483ff31402392961362e9bc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f73a8edc2ccc6ec72c37d5c578e7592d2e1f9922"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68172.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68172"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:03:55.691945245Z"}}