CVE-2026-63991: Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()

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

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

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

Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()

The skb_clone() function can return NULL if memory allocation fails.
send_mcast_pkt() calls skb_clone() without checking the return value, which
can lead to a NULL pointer dereference in send_pkt() when it dereferences
skb->data.
Add a NULL check after skb_clone() and skip the peer if the clone fails.

The Linux kernel CVE team has assigned CVE-2026-63991 to this issue.


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

	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 5.10.259 with commit 9afcb5ea080af13aab37930da627db43bd277665
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 5.15.210 with commit 9903a04becf059e44cccf625e23689b7d4378384
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 6.1.176 with commit d630c4b25f36e0e68461561e4c70957ec37fdedd
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 6.6.143 with commit b06203ac5f12929d79146bb9f063c2af1d679e63
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 6.12.93 with commit 3d5d81d294ba09487c86bc4ba33dc4a4bec5d215
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 6.18.35 with commit e673889a35a5e4c586d0fae67d8755ca4367d3e2
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 7.0.12 with commit 2061d080a013c0ec0a56162cd501fb36d2befc26
	Issue introduced in 3.14 with commit 18722c247023035b9e2e2a08a887adec2a9a6e49 and fixed in 7.1 with commit 3c40d381ce04f9575a5d8b542898183c3b4b38dc

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-2026-63991
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/6lowpan.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/9afcb5ea080af13aab37930da627db43bd277665
	https://git.kernel.org/stable/c/9903a04becf059e44cccf625e23689b7d4378384
	https://git.kernel.org/stable/c/d630c4b25f36e0e68461561e4c70957ec37fdedd
	https://git.kernel.org/stable/c/b06203ac5f12929d79146bb9f063c2af1d679e63
	https://git.kernel.org/stable/c/3d5d81d294ba09487c86bc4ba33dc4a4bec5d215
	https://git.kernel.org/stable/c/e673889a35a5e4c586d0fae67d8755ca4367d3e2
	https://git.kernel.org/stable/c/2061d080a013c0ec0a56162cd501fb36d2befc26
	https://git.kernel.org/stable/c/3c40d381ce04f9575a5d8b542898183c3b4b38dc