CVE-2026-98458: Bluetooth: ISO: release unused CIS holds after channel attach

CVE-2026-98458: Bluetooth: ISO: release unused CIS holds after channel attach

[Greg Kroah-Hartman]

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

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

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

Bluetooth: ISO: release unused CIS holds after channel attach

hci_bind_cis() and hci_connect_cis() return one hci_conn hold for the
ISO layer.  A new channel association consumes that hold, which is
eventually released by iso_conn_free().

There are two cases where iso_chan_add() does not create an association:
it returns success when the socket is already attached to the same
iso_conn, and it returns -EBUSY when another socket is attached.  The
hold returned for the current call is unused in both cases.  This occurs
when deferred setup calls iso_connect_cis() again for its existing
socket, or when another socket attempts to reuse the CIS.

Detect the idempotent case while the connection is locked and release
the unused hold after iso_chan_add().  Also release it on -EBUSY.  Do not
drop it for other errors: a newly allocated iso_conn releases the
transferred hold when its last temporary reference is put.

The Linux kernel CVE team has assigned CVE-2026-98458 to this issue.


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

	Issue introduced in 6.6 with commit 69997d50ec574be816b4ee8f9cee52ebbd53f8bd and fixed in 6.12.113 with commit e0e8b70207eaf27aee0a05ec5bf2d1b6bcb004d1
	Issue introduced in 6.6 with commit 69997d50ec574be816b4ee8f9cee52ebbd53f8bd and fixed in 6.18.55 with commit ed4c026cc4094dfb7a329b9d8df0ddd0be1b2458
	Issue introduced in 6.6 with commit 69997d50ec574be816b4ee8f9cee52ebbd53f8bd and fixed in 7.2.9 with commit e5fcca51177f224604e3a8c926ffd5edbeb58b09
	Issue introduced in 6.6 with commit 69997d50ec574be816b4ee8f9cee52ebbd53f8bd and fixed in 7.3-rc5 with commit 0fcd4dad555c96e0bd3a1b8c569f989be85c7341

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-2026-98458
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/e0e8b70207eaf27aee0a05ec5bf2d1b6bcb004d1
	https://git.kernel.org/stable/c/ed4c026cc4094dfb7a329b9d8df0ddd0be1b2458
	https://git.kernel.org/stable/c/e5fcca51177f224604e3a8c926ffd5edbeb58b09
	https://git.kernel.org/stable/c/0fcd4dad555c96e0bd3a1b8c569f989be85c7341