CVE-2026-89785fs/ntfs3: fix out-of-bounds read of INDEX_ROOT in reparse/objid init

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_init (fs/ntfs3/fsntfs.c:2306) Read of size 4 at addr ffff88801219dc00 by task mount ntfs_reparse_init (fs/ntfs3/fsntfs.c:2306) ntfs_fill_super (fs/ntfs3/super.c:1604) get_tree_bdev_flags (fs/super.c:1703) vfs_get_tree (fs/super.c:1758) path_mount (fs/namespace.c:4131) __x64_sys_mount (fs/namespace.c:4360)

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Sep 16, 2026

First seen by InfoSec Signals

Oct 9, 2026

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