From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89699: nfsd: validate symlink target length in NFSv4 CREATE
Date: Fri, 11 Sep 2026 21:46:28 +0200 [thread overview]
Message-ID: <2026091155-CVE-2026-89699-6e8e@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
nfsd: validate symlink target length in NFSv4 CREATE
nfsd4_decode_create() accepts an unbounded cr_datalen from the wire for
NF4LNK symlink targets, allowing a client to force a kmalloc of up to
the maximum RPC payload size (several MiB) per COMPOUND op that persists
until compound teardown. The VFS rejects oversized targets with
ENAMETOOLONG, but the allocation has already occurred.
Reject cr_datalen == 0 early with nfserr_inval and cr_datalen greater
than NFS4_MAXPATHLEN (PATH_MAX) with nfserr_nametoolong to bound the
allocation.
The Linux kernel CVE team has assigned CVE-2026-89699 to this issue.
Affected and fixed versions
===========================
Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.109 with commit b24843ea3de1676b29902457b38507c95a80649b
Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.50 with commit 895a485cd3758031ef9993c0d53cf19ce8fb4ccc
Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.2.4 with commit 45ec115cbfecb4b3cfab7fca6f73d1b60696a25a
Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.3-rc1 with commit 041f57056e5fb9c80adc088269322d2c61074406
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-2026-89699
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/nfsd/nfs4xdr.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/b24843ea3de1676b29902457b38507c95a80649b
https://git.kernel.org/stable/c/895a485cd3758031ef9993c0d53cf19ce8fb4ccc
https://git.kernel.org/stable/c/45ec115cbfecb4b3cfab7fca6f73d1b60696a25a
https://git.kernel.org/stable/c/041f57056e5fb9c80adc088269322d2c61074406
reply other threads:[~2026-09-11 20:05 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=2026091155-CVE-2026-89699-6e8e@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