CVE-2026-63870 ieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit()
A Linux kernel vulnerability allows denial of service via uninitialized memory access when non-IPv6 packets are sent over 6LoWPAN interfaces.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63870?
CVE-2026-63870 is a high-severity vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit()
The aoe driver (or similar) generates a non-IPv6 packet (e.g., ETH_P_AOE) and queues it for transmission via dev_queue_xmit() on a 6LoWPAN interface (configured by the user or test case).
Since the packet is not IPv6, the 6LoWPAN header_ops->create function (lowpan_header_create or header_create) returns early without initializing the lowpan_addr_info structure in the skb headroom.
In the transmit function (lowpan_xmit), the driver calls lowpan_header (or setup_header) which unconditionally copies and uses the lowpan_addr_info from the headroom, which contains uninitialized data.
Fix this by dropping non IPv6 packets.
A similar fix is needed in net/bluetooth/6lowpan.c bt_xmit().
Which versions are affected by CVE-2026-63870?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63870?
Apply the vendor's patch.
Is CVE-2026-63870 being exploited?
There is no known exploitation of CVE-2026-63870 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63870, DEBIAN-CVE-2026-63870, GHSA-phq6-q8j5-j858, ROOT-OS-UBUNTU-2204-CVE-2026-63870, UBUNTU-CVE-2026-63870.