CVE-2026-89785 is a vulnerability in Linux Kernel
Published on September 16, 2026
fs/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)
Products Associated with CVE-2026-89785
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Affected Versions
Linux:- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below eb80003744e32a7366a523015e4acfe0a2ac7d88 is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below bd631e2005290a55c8edda87363bc0d594c01705 is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below 94fce1d3e74fe011e21f17490ba58491709fd7e5 is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below 66c074eab6f966fbe48a0fc4b3a45b2a2e2df527 is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below 64bb6000bfbdf241a6dd578199acd90321a4243e is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below 72caafbc95c5dca8266a942b8e96ad81d8d9adc7 is affected.
- Version 82cae269cfa953032fbb8980a7d554d60fb00b17 and below 2064bc663f89e61b8681c1fb9d1ce445de72063d is affected.
- Version 5.15 is affected.
- Before 5.15 is unaffected.
- Version 5.15.221, <= 5.15.* is unaffected.
- Version 6.1.188, <= 6.1.* is unaffected.
- Version 6.6.157, <= 6.6.* is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.52, <= 6.18.* is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.