CVE-2026-63870: Linux kernel · ieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +68
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected linux-aws kernel versions. The fix drops non-IPv6 packets in the 6LoWPAN transmit path to prevent use of uninitialized memory. Users should update to patched kernel versions as per the Ubuntu security advisory USN-8726-1. No additional mitigation actions are required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's ieee802154 6LoWPAN implementation allowed non-IPv6 packets to be processed improperly, leading to use of uninitialized memory. This was due to the lowpan_xmit function accepting packets other than IPv6, causing uninitialized data usage in packet headers. The flaw was fixed by dropping non-IPv6 packets in the transmit path. The issue affects multiple linux-aws kernel versions and has a CVSS score of 7.8.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63870 (opens in a new tab)
- git.kernel.org/stable/c/1a827b95e62b4cbe851ae7cc9c961cdfa769cca4 (opens in a new tab)
- git.kernel.org/stable/c/285b0842f2e01c3edf805f1fd64da11d9b7f6b4c (opens in a new tab)
- git.kernel.org/stable/c/3150e6d3223dfc356308125cabf9c34169842d2a (opens in a new tab)
- git.kernel.org/stable/c/3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3 (opens in a new tab)
- git.kernel.org/stable/c/87172cc8dc49aaf54407a31edffb0232f8cb93ab (opens in a new tab)
- git.kernel.org/stable/c/8da95cb6ad7d656c871e776a9c7b77e894d6d89c (opens in a new tab)
- git.kernel.org/stable/c/af07fffbd53ddc3ec3c2a4ca914f27899fa89bca (opens in a new tab)
- git.kernel.org/stable/c/c1819c8defa235c7beda859bc185b1c429a55ecd (opens in a new tab)
- ubuntu.com/security/CVE-2026-63870 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63870 (opens in a new tab)
- git.kernel.org/linus/3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-1 (opens in a new tab)