CVE-2026-64128: Bluetooth: ISO: drop ISO_END frames received without prior ISO_START

From: Greg Kroah-Hartman <[email protected]>

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

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

Bluetooth: ISO: drop ISO_END frames received without prior ISO_START

ISO data PDUs carry a packet-boundary flag indicating START, CONT, END
or SINGLE. The ISO_CONT branch of iso_recv() guards against a missing
ISO_START by checking conn->rx_len before touching conn->rx_skb, but
ISO_END does not.

If a peer sends an ISO_END as the first packet on a fresh ISO
connection, conn->rx_skb is still NULL and conn->rx_len is zero, so
skb_put(conn->rx_skb, ...) dereferences NULL and oopses. For BIS,
where receivers sync to a broadcaster without pairing, any broadcaster
on the air can trigger this.

Mirror the ISO_CONT check at the top of ISO_END so a stray end fragment
is logged and dropped instead of crashing the host.

The Linux kernel CVE team has assigned CVE-2026-64128 to this issue.


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

	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.1.175 with commit 1c3d1e1696b72579b970e17999c503a14535205b
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.6.142 with commit 3af41ee7ebecb0d5c8a504861f6cfad31345310f
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.12.92 with commit 39f4a82e80c8f5ed2d6952d73fbafc895721a728
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 6.18.34 with commit 61f2410a96dee808029e2ae4d6ef2dd635f3477f
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 7.0.11 with commit e3a799881c12d27596232636a607e2e3fa448d63
	Issue introduced in 6.0 with commit ccf74f2390d60a2f9a75ef496d2564abb478f46a and fixed in 7.1 with commit 84c24fb151fc1179355296d7ff29129ac7c42129

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-2026-64128
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/bluetooth/iso.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/1c3d1e1696b72579b970e17999c503a14535205b
	https://git.kernel.org/stable/c/3af41ee7ebecb0d5c8a504861f6cfad31345310f
	https://git.kernel.org/stable/c/39f4a82e80c8f5ed2d6952d73fbafc895721a728
	https://git.kernel.org/stable/c/61f2410a96dee808029e2ae4d6ef2dd635f3477f
	https://git.kernel.org/stable/c/e3a799881c12d27596232636a607e2e3fa448d63
	https://git.kernel.org/stable/c/84c24fb151fc1179355296d7ff29129ac7c42129