From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89565: ipip: fix skb leak in collect_md mode when metadata_dst allocation fails
Date: Fri, 11 Sep 2026 21:44:14 +0200 [thread overview]
Message-ID: <2026091124-CVE-2026-89565-6060@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
ipip: fix skb leak in collect_md mode when metadata_dst allocation fails
In collect_md mode ipip_tunnel_rcv() returns 0 without freeing the skb
when ip_tun_rx_dst() fails to allocate the metadata_dst. ipip_rcv() and
mplsip_rcv() are registered as xfrm_tunnel handlers, so tunnel4_rcv()
and tunnelmpls4_rcv() read the zero return as "the packet has been
consumed" and do not free it either. The skb is leaked.
The other tunnel drivers all dispose of the packet at this point:
ip6_tunnel.c jumps to its drop label, ip_gre.c and ip6_gre.c return
PACKET_REJECT, which makes gre_rcv() free the skb. Only ipip returns 0.
Jump to the existing drop label instead. It frees the skb and still
returns 0, so the packet keeps being reported as consumed, which is what
we want here: the outer header has already been pulled, and neither the
remaining handlers nor an ICMP unreachable have any use for it.
Triggering this needs an ipip or mplsip tunnel in collect_md mode and an
atomic allocation failure, which is why it has gone unnoticed.
The Linux kernel CVE team has assigned CVE-2026-89565 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.9 with commit cfc7381b3002756b1dcada32979e942aa3126e31 and fixed in 6.12.109 with commit 6d8c5b266d0035a061573843a7243be068eb6118
Issue introduced in 4.9 with commit cfc7381b3002756b1dcada32979e942aa3126e31 and fixed in 6.18.50 with commit 31e4be21dacee49395013caae28576484a049a4f
Issue introduced in 4.9 with commit cfc7381b3002756b1dcada32979e942aa3126e31 and fixed in 7.2.4 with commit fd01f1a3ed4a189a784654f7c69eb565872f2e12
Issue introduced in 4.9 with commit cfc7381b3002756b1dcada32979e942aa3126e31 and fixed in 7.3-rc1 with commit 6776efe4a52f289a3fc18f8adf19b035a7d8e1bb
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-2026-89565
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:
net/ipv4/ipip.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/6d8c5b266d0035a061573843a7243be068eb6118
https://git.kernel.org/stable/c/31e4be21dacee49395013caae28576484a049a4f
https://git.kernel.org/stable/c/fd01f1a3ed4a189a784654f7c69eb565872f2e12
https://git.kernel.org/stable/c/6776efe4a52f289a3fc18f8adf19b035a7d8e1bb
reply other threads:[~2026-09-11 19:56 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=2026091124-CVE-2026-89565-6060@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.