CVE-2026-89785
fs/ntfs3: fix out-of-bounds read of INDEX_ROOT in reparse/objid init
Description
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)
INFO
Published Date :
Sept. 16, 2026, 9:17 a.m.
Last Modified :
Sept. 16, 2026, 9:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Apply the kernel patch for ntfs3.
- Update the Linux kernel to a fixed version.
- Ensure kernel modules are updated.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-89785.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89785 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89785
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-89785 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89785 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 16, 2026
Action Type Old Value New Value Added Description 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) Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89785.json">CVE-2026-89785</a> Added Reference https://git.kernel.org/stable/c/2064bc663f89e61b8681c1fb9d1ce445de72063d Added Reference https://git.kernel.org/stable/c/64bb6000bfbdf241a6dd578199acd90321a4243e Added Reference https://git.kernel.org/stable/c/66c074eab6f966fbe48a0fc4b3a45b2a2e2df527 Added Reference https://git.kernel.org/stable/c/72caafbc95c5dca8266a942b8e96ad81d8d9adc7 Added Reference https://git.kernel.org/stable/c/94fce1d3e74fe011e21f17490ba58491709fd7e5 Added Reference https://git.kernel.org/stable/c/bd631e2005290a55c8edda87363bc0d594c01705 Added Reference https://git.kernel.org/stable/c/eb80003744e32a7366a523015e4acfe0a2ac7d88