CVE-2026-63990: Linux kernel · bonding: refuse to enslave CAN devices
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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 +65
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 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
An official patch is available that fixes this vulnerability by refusing to enslave CAN devices in the bonding driver. Users should apply the Linux kernel updates that include this fix. The Ubuntu advisory USN-8593-1 confirms the availability of this patch. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel bonding driver allowed CAN (Controller Area Network) devices to be enslaved to a bonding master, causing a kernel paging request crash due to a null-pointer dereference. This occurs because the bonding driver assumes Ethernet-like behavior, which is incompatible with CAN devices. The issue has been fixed by refusing to enslave CAN devices, preventing the crash.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63990 (opens in a new tab)
- git.kernel.org/stable/c/02f1c87ded33b43d48b4a1d665da15f2157b30d8 (opens in a new tab)
- git.kernel.org/stable/c/41e8478c4cd896d3abbe33d41afc90c84ac66602 (opens in a new tab)
- git.kernel.org/stable/c/563090e5d450c665f70d955a39f9587afc7842eb (opens in a new tab)
- git.kernel.org/stable/c/69b78b5f3033272e53a2dc2dad675962654a5b38 (opens in a new tab)
- git.kernel.org/stable/c/8ba68464e4787b6a7ec938826e16124df20fd23d (opens in a new tab)
- git.kernel.org/stable/c/9ea8a648d9120f7652bcde1ce2c4ad66871af707 (opens in a new tab)
- git.kernel.org/stable/c/f4d78a81f57df82e9d82a2c07471fed1a1235893 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63990 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63990 (opens in a new tab)
- git.kernel.org/linus/8ba68464e4787b6a7ec938826e16124df20fd23d (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (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-8903-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8905-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8906-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8904-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8903-2 (opens in a new tab)