{"id":"CVE-2025-37818","summary":"LoongArch: Return NULL from huge_pte_offset() for invalid PMD","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Return NULL from huge_pte_offset() for invalid PMD\n\nLoongArch's huge_pte_offset() currently returns a pointer to a PMD slot\neven if the underlying entry points to invalid_pte_table (indicating no\nmapping). Callers like smaps_hugetlb_range() fetch this invalid entry\nvalue (the address of invalid_pte_table) via this pointer.\n\nThe generic is_swap_pte() check then incorrectly identifies this address\nas a swap entry on LoongArch, because it satisfies the \"!pte_present()\n&& !pte_none()\" conditions. This misinterpretation, combined with a\ncoincidental match by is_migration_entry() on the address bits, leads to\nkernel crashes in pfn_swap_entry_to_page().\n\nFix this at the architecture level by modifying huge_pte_offset() to\ncheck the PMD entry's content using pmd_none() before returning. If the\nentry is invalid (i.e., it points to invalid_pte_table), return NULL\ninstead of the pointer to the slot.","modified":"2026-04-02T12:47:30.687980Z","published":"2025-05-08T06:26:13.322Z","related":["MGASA-2025-0182","MGASA-2025-0183"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37818.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2ca9380b12711afe95b3589bd82b59623b3c96b3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/34256805720993e37adf6127371a1265aea8376a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/51424fd171cee6a33f01f7c66b8eb23ac42289d4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b49f085cd671addbda4802d6b9382513f7dd0f30"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bd51834d1cf65a2c801295d230c220aeebf87a73"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37818.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-37818"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fa96b57c149061f71a70bd6582d995f6424fbbf4"},{"fixed":"34256805720993e37adf6127371a1265aea8376a"},{"fixed":"2ca9380b12711afe95b3589bd82b59623b3c96b3"},{"fixed":"51424fd171cee6a33f01f7c66b8eb23ac42289d4"},{"fixed":"b49f085cd671addbda4802d6b9382513f7dd0f30"},{"fixed":"bd51834d1cf65a2c801295d230c220aeebf87a73"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-37818.json"}}],"schema_version":"1.7.5"}