CVE-2026-80987: NTB: ntb_transport: Reject oversized TX buffers

CVE-2026-80987: NTB: ntb_transport: Reject oversized TX buffers

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

NTB: ntb_transport: Reject oversized TX buffers

ntb_process_tx() handles an oversized buffer by calling tx_handler()
with a NULL data pointer and returning success. ntb_netdev therefore
neither frees the skb in its completion callback nor takes its enqueue
error path, leaking it.

Reject oversized buffers in ntb_transport_tx_enqueue() before acquiring
a queue entry and return -EMSGSIZE. The caller retains ownership of the
buffer, and the preceding netdev patch frees the skb when enqueue
returns this permanent error.

The Linux kernel CVE team has assigned CVE-2026-80987 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.9 with commit fce8a7bb5b4bfb8a27324703fd5b002ee9247e90 and fixed in 6.12.109 with commit a7f22105a7df8c7fd74d0af27ace6fa94fe03d87
	Issue introduced in 3.9 with commit fce8a7bb5b4bfb8a27324703fd5b002ee9247e90 and fixed in 6.18.50 with commit 6b6bbc6c878d64eacc60877df49fce7b1b6a08d0
	Issue introduced in 3.9 with commit fce8a7bb5b4bfb8a27324703fd5b002ee9247e90 and fixed in 7.2.4 with commit 75a604e9f1cfdebda421062fdf42225ca32154cd
	Issue introduced in 3.9 with commit fce8a7bb5b4bfb8a27324703fd5b002ee9247e90 and fixed in 7.3-rc1 with commit a4f2387db6f1cc2f03abba7f3a6807ad61e26ff7

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-2026-80987
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/ntb/ntb_transport.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/a7f22105a7df8c7fd74d0af27ace6fa94fe03d87
	https://git.kernel.org/stable/c/6b6bbc6c878d64eacc60877df49fce7b1b6a08d0
	https://git.kernel.org/stable/c/75a604e9f1cfdebda421062fdf42225ca32154cd
	https://git.kernel.org/stable/c/a4f2387db6f1cc2f03abba7f3a6807ad61e26ff7