CVE-2026-89785CVE-2026-89785

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: fix out-of-bounds read of INDEX_ROOT in reparse/objid init ntfs_reparse_init() and ntfs_objid_init() parse the index root of the $Extend/$Reparse and $Extend/$ObjId metafiles (the INDEX_ROOT attributes named $R and $O). They read its type and rule fields through resident_data(), which does not check that the resident attribute is large enough to hold them. mi_enum_attr() accepts a resident attribute with data_off == asize and data_size == 0. For such an attribute placed last in its MFT record, resident_data() returns a pointer to the end of the record_size buffer, so reading root->type / root->rule reads past the allocation. Use resident_data_ex(attr, sizeof(struct INDEX_ROOT)) and bail out when it returns NULL, as ntfs_security_init() already does for $SDH / $SII. The attribute is only parsed while mounting a crafted image, so this needs CAP_SYS_ADMIN. BUG: KASAN: slab-out-of-bounds in ntfs_reparse_in