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Fencer Vulns
no cvss —

CVE-2026-89785 json

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

published 2026-09-16 54 d ago modified 2026-10-19 21 d ago also EUVD-2026-80306

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

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)

Patch / fix

  • Linux Linux 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-89785

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-89785

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.7-1.1

opensuse advisories openSUSE-SU-2026:11880-1

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-101345

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89785 updated cvss 5.5

kernel: fs/ntfs3: fix out-of-bounds read of INDEX_ROOT in reparse/objid init

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    +1 more products
    Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.