ghsa-4q4q-jv3m-fqjr
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Return NULL from huge_pte_offset() for invalid PMD
LoongArch's huge_pte_offset() currently returns a pointer to a PMD slot even if the underlying entry points to invalid_pte_table (indicating no mapping). Callers like smaps_hugetlb_range() fetch this invalid entry value (the address of invalid_pte_table) via this pointer.
The generic is_swap_pte() check then incorrectly identifies this address as a swap entry on LoongArch, because it satisfies the "!pte_present() && !pte_none()" conditions. This misinterpretation, combined with a coincidental match by is_migration_entry() on the address bits, leads to kernel crashes in pfn_swap_entry_to_page().
Fix this at the architecture level by modifying huge_pte_offset() to check the PMD entry's content using pmd_none() before returning. If the entry is invalid (i.e., it points to invalid_pte_table), return NULL instead of the pointer to the slot.
{ "affected": [], "aliases": [ "CVE-2025-37818" ], "database_specific": { "cwe_ids": [], "github_reviewed": false, "github_reviewed_at": null, "nvd_published_at": "2025-05-08T07:15:53Z", "severity": null }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Return NULL from huge_pte_offset() for invalid PMD\n\nLoongArch\u0027s 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\u0026\u0026 !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\u0027s 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.", "id": "GHSA-4q4q-jv3m-fqjr", "modified": "2025-05-08T09:30:24Z", "published": "2025-05-08T09:30:24Z", "references": [ { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-37818" }, { "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" } ], "schema_version": "1.4.0", "severity": [] }
Sightings
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