{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63870","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.017Z","datePublished":"2026-07-19T14:18:39.113Z","dateUpdated":"2026-08-05T12:36:45.663Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:36:45.663Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit()\n\nThe aoe driver (or similar) generates a non-IPv6 packet\n(e.g., ETH_P_AOE) and queues it for transmission via dev_queue_xmit()\non a 6LoWPAN interface (configured by the user or test case).\n\nSince the packet is not IPv6, the 6LoWPAN header_ops->create function\n(lowpan_header_create or header_create) returns early without initializing\nthe lowpan_addr_info structure in the skb headroom.\n\nIn the transmit function (lowpan_xmit), the driver calls lowpan_header\n(or setup_header) which unconditionally copies and uses the lowpan_addr_info\nfrom the headroom, which contains uninitialized data.\n\nFix this by dropping non IPv6 packets.\n\nA similar fix is needed in net/bluetooth/6lowpan.c bt_xmit()."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The flaw is in the transmit path (`lowpan_xmit`) reached only when locally queued skbs are sent via `dev_queue_xmit()` (syzbot: AoE → `aoenet.c:tx` → `lowpan_xmit`), not from remote 802.15.4 packet reception.\nAC:L - An attacker who can create a 6LoWPAN interface and queue non-IPv6 packets (or misconfigure AoE onto it) reliably triggers the uninitialized read; syzbot reproduced it deterministically with no race or rare layout dependency.\nPR:L - Exploitation requires creating a `lowpan` RTNL link (`CAP_NET_ADMIN`, obtainable in a user namespace) and transmitting non-IPv6 frames via `AF_PACKET` or a misbound driver; no real-root-only capability is strictly required on typical userns-enabled systems.\nUI:N - No victim interaction is needed beyond the attacker (or fuzzer) configuring the interface and injecting the malformed transmit; exploitation is fully attacker-driven.\nS:U - Impact is confined to kernel memory handling and 802.15.4 transmission on the same host; it does not cross a VM, container, or IOMMU security boundary.\nC:H - `lowpan_header()` copies uninitialized slab contents from skb headroom (`KMSAN: uninit-value` at `tx.c:231/240`) and uses them in 802.15.4 address fields, leaking kernel heap bytes that may be encoded into transmitted WPAN frames.\nI:H - Uninitialized `ieee802154_addr` values drive `wpan_dev_hard_header()` and frame transmission, allowing heap-spray-influenced 802.15.4 destinations and corrupted over-the-air frames rather than only a benign drop.\nA:H - Successful transmission of malformed WPAN frames with attacker-influenced addressing can disrupt 802.15.4 mesh/IoT availability, and memory-safety bugs on the xmit path can escalate to kernel faults under heap-controlled conditions."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ieee802154/6lowpan/tx.c"],"versions":[{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"af07fffbd53ddc3ec3c2a4ca914f27899fa89bca","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"3150e6d3223dfc356308125cabf9c34169842d2a","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"8da95cb6ad7d656c871e776a9c7b77e894d6d89c","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"1a827b95e62b4cbe851ae7cc9c961cdfa769cca4","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"c1819c8defa235c7beda859bc185b1c429a55ecd","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"285b0842f2e01c3edf805f1fd64da11d9b7f6b4c","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"87172cc8dc49aaf54407a31edffb0232f8cb93ab","status":"affected","versionType":"git"},{"version":"4dc315e267fe4a3c863fec21f26aa0a418c3f07a","lessThan":"3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ieee802154/6lowpan/tx.c"],"versions":[{"version":"4.0","status":"affected"},{"version":"0","lessThan":"4.0","status":"unaffected","versionType":"semver"},{"version":"5.10.259","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.210","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.176","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.143","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.94","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.36","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.13","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.12.94"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"6.18.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.0.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.0","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/af07fffbd53ddc3ec3c2a4ca914f27899fa89bca"},{"url":"https://git.kernel.org/stable/c/3150e6d3223dfc356308125cabf9c34169842d2a"},{"url":"https://git.kernel.org/stable/c/8da95cb6ad7d656c871e776a9c7b77e894d6d89c"},{"url":"https://git.kernel.org/stable/c/1a827b95e62b4cbe851ae7cc9c961cdfa769cca4"},{"url":"https://git.kernel.org/stable/c/c1819c8defa235c7beda859bc185b1c429a55ecd"},{"url":"https://git.kernel.org/stable/c/285b0842f2e01c3edf805f1fd64da11d9b7f6b4c"},{"url":"https://git.kernel.org/stable/c/87172cc8dc49aaf54407a31edffb0232f8cb93ab"},{"url":"https://git.kernel.org/stable/c/3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3"}],"title":"ieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit()","x_generator":{"engine":"bippy-1.2.0"}}}}