From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89611: ntfs: validate non-resident attribute offsets
Date: Fri, 11 Sep 2026 21:45:00 +0200 [thread overview]
Message-ID: <2026091135-CVE-2026-89611-2a16@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
ntfs: validate non-resident attribute offsets
ntfs_attr_update_meta() shifts the attribute name when converting between
non-sparse and sparse attributes. Converting to sparse also adds the
compressed_size field before the name and mapping pairs, requiring eight
additional bytes in the attribute record.
However, the validator does not check that name_offset is within safe
boundaries for these operations or that the additional space is available.
A malicious MFT record could set name_offset such that:
1. The name is positioned at the very end of a non-sparse attribute.
Converting to sparse would shift the name forward by 8 bytes,
writing beyond the attribute boundary.
2. The name overlaps with the mapping pairs, causing corruption during
conversion.
Add validation to ensure:
- For named attributes, name_offset is within valid bounds
- Name does not extend beyond the attribute or overlap with mapping pairs
- For non-sparse, non-compressed attributes, eight bytes are available
after mapping_pairs_offset for the compressed_size field
The space check also covers unnamed attributes, for which name_offset = 0
is valid and no name range needs to be checked.
The Linux kernel CVE team has assigned CVE-2026-89611 to this issue.
Affected and fixed versions
===========================
Fixed in 7.2.4 with commit cd7b3dc7557faadeea626034e3bac68a449851ef
Fixed in 7.3-rc1 with commit a83e82b0ec3ae523028e24813f23f18b43e8fc1c
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-89611
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
fs/ntfs/attrib.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/cd7b3dc7557faadeea626034e3bac68a449851ef
https://git.kernel.org/stable/c/a83e82b0ec3ae523028e24813f23f18b43e8fc1c
reply other threads:[~2026-09-11 19:58 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2026091135-CVE-2026-89611-2a16@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=cve@kernel.org \
--cc=gregkh@kernel.org \
--cc=linux-cve-announce@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox