From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-68299: vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets
Date: Mon, 10 Aug 2026 14:00:16 +0200 [thread overview]
Message-ID: <2026081029-CVE-2026-68299-d85c@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets
vmxnet3_get_hdr_len() assumes gdesc->rcd.v4/v6/tcp always describe the
outer header, but for a Geneve-encapsulated packet the device can set
them based on the inner header instead, signalled by the
VMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the
function never skips the outer encapsulation, this mismatch triggers:
- BUG_ON(hdr.ipv4->protocol != IPPROTO_TCP), because the outer
protocol is UDP (Geneve), not TCP.
- BUG_ON(hdr.eth->h_proto != ...), when the tunnel's outer and inner
IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa).
Check VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the
function cannot locate the inner header it would need to parse. Also
convert the remaining BUG_ON()s in this function to return 0
defensively.
The Linux kernel CVE team has assigned CVE-2026-68299 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.2 with commit 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc and fixed in 6.6.148 with commit 667b6e52048eaf4dbcf1707ed87ffd44abb9cb38
Issue introduced in 4.2 with commit 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc and fixed in 6.12.101 with commit 28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8
Issue introduced in 4.2 with commit 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc and fixed in 6.18.42 with commit 4fdb0f162ccdbe9626863b10003855703253fa29
Issue introduced in 4.2 with commit 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc and fixed in 7.1.6 with commit b28596baf87e25a078789f1c05817c8a3bf71257
Issue introduced in 4.2 with commit 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc and fixed in 7.2-rc5 with commit 34a71f5361fc3adb5b7138da78750b0d535a8252
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-2026-68299
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:
drivers/net/vmxnet3/vmxnet3_drv.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/667b6e52048eaf4dbcf1707ed87ffd44abb9cb38
https://git.kernel.org/stable/c/28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8
https://git.kernel.org/stable/c/4fdb0f162ccdbe9626863b10003855703253fa29
https://git.kernel.org/stable/c/b28596baf87e25a078789f1c05817c8a3bf71257
https://git.kernel.org/stable/c/34a71f5361fc3adb5b7138da78750b0d535a8252
reply other threads:[~2026-08-10 12:09 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=2026081029-CVE-2026-68299-d85c@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.