From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-46321: tun: free page on short-frame rejection in tun_xdp_one()
Date: Tue, 9 Jun 2026 14:10:27 +0200 [thread overview]
Message-ID: <2026060925-CVE-2026-46321-8e46@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
tun: free page on short-frame rejection in tun_xdp_one()
tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without
freeing the page that vhost_net_build_xdp() allocated for it.
tun_sendmsg() discards that -EINVAL and still returns total_len, so
vhost_tx_batch() takes the success path and never frees the page; each
short frame in a batch leaks one page-frag chunk.
A local process that can open /dev/net/tun and /dev/vhost-net can hit
this path: it attaches a tun/tap device as the vhost-net backend and
feeds TX descriptors whose length minus the virtio-net header is below
ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a
tight submission loop exhausts host memory and triggers an OOM panic.
Free the page before returning -EINVAL, matching the XDP-program error
path in the same function.
The Linux kernel CVE team has assigned CVE-2026-46321 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.11 with commit 049584807f1d797fc3078b68035450a9769eb5c3 and fixed in 6.12.93 with commit 69863ff2720a0e9871f1a5710f2a33a94217fee0
Issue introduced in 6.11 with commit 049584807f1d797fc3078b68035450a9769eb5c3 and fixed in 6.18.35 with commit 37a1c268c2c8090bf4dc552d732bd23ba36f8eb0
Issue introduced in 6.11 with commit 049584807f1d797fc3078b68035450a9769eb5c3 and fixed in 7.0.12 with commit 98c67be9eb9de72465a071949e84a3cdb8fab5a3
Issue introduced in 6.11 with commit 049584807f1d797fc3078b68035450a9769eb5c3 and fixed in 7.1-rc6 with commit f4feb1e20058e407cb00f45aff47f5b7e19a6bbf
Issue introduced in 5.4.281 with commit 32b0aaba5dbc85816898167d9b5d45a22eae82e9
Issue introduced in 5.10.223 with commit 6100e0237204890269e3f934acfc50d35fd6f319
Issue introduced in 5.15.164 with commit 589382f50b4a5d90d16d8bc9dcbc0e927a3e39b2
Issue introduced in 6.1.102 with commit ad6b3f622ccfb4bfedfa53b6ebd91c3d1d04f146
Issue introduced in 6.6.43 with commit d5ad89b7d01ed4e66fd04734fc63d6e78536692a
Issue introduced in 6.9.12 with commit a9d1c27e2ee3b0ea5d40c105d6e728fc114470bb
Issue introduced in 6.10.2 with commit 8418f55302fa1d2eeb73e16e345167e545c598a5
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-2026-46321
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/tun.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/69863ff2720a0e9871f1a5710f2a33a94217fee0
https://git.kernel.org/stable/c/37a1c268c2c8090bf4dc552d732bd23ba36f8eb0
https://git.kernel.org/stable/c/98c67be9eb9de72465a071949e84a3cdb8fab5a3
https://git.kernel.org/stable/c/f4feb1e20058e407cb00f45aff47f5b7e19a6bbf
reply other threads:[~2026-06-09 12:11 UTC|newest]
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