--- title: "CVE-2018-12904\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2018-12904?format=md keywords: index, follow --- # CVE-2018-12904 Publication date 27 June 2018 Last updated 4 July 2026 --- Ubuntu priority **Low** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **4.9 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2018-12904?format=md#impact-score) Toggle side navigation ## Description In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL. ### From the Ubuntu Security Team Felix Wilhelm discovered that the KVM implementation in the Linux kernel did not properly perform permission checks in some situations when nested virtualization is used. An attacker in a guest VM could possibly use this to escape into an outer VM or the host OS. [Read the notes from the security team](https://ubuntu.com/security/CVE-2018-12904?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | linux | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-33.36 | | 17.10 artful | Ignored end of life | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not affected | | linux-aws | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1020.20 | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not affected | | linux-azure | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1022.23 | | 17.10 artful | Not in release | | 16.04 LTS xenial | Fixed 4.15.0-1022.22~16.04.1 | | 14.04 LTS trusty | Not affected | | linux-azure-edge | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not affected | | 17.10 artful | Not in release | | 16.04 LTS xenial | Fixed 4.15.0-1022.23 | | 14.04 LTS trusty | Not in release | | linux-euclid | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-flo | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-gcp | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1018.19 | | 17.10 artful | Not in release | | 16.04 LTS xenial | Fixed 4.15.0-1018.19~16.04.2 | | 14.04 LTS trusty | Not in release | | linux-gke | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Ignored end of standard support | | 14.04 LTS trusty | Not in release | | linux-goldfish | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-grouper | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-hwe | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not affected | | 17.10 artful | Not in release | | 16.04 LTS xenial | Fixed 4.15.0-33.36~16.04.1 | | 14.04 LTS trusty | Not in release | | linux-hwe-edge | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not affected | | 17.10 artful | Not in release | | 16.04 LTS xenial | Fixed 4.15.0-33.36~16.04.1 | | 14.04 LTS trusty | Not in release | | linux-kvm | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1020.20 | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | | linux-lts-trusty | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-lts-utopic | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-lts-vivid | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-lts-wily | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-lts-xenial | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not affected | | linux-maguro | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-mako | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-manta | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not in release | | 17.10 artful | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | linux-oem | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1017.20 | | 17.10 artful | Not in release | | 16.04 LTS xenial | Ignored end of standard support, was needed | | 14.04 LTS trusty | Not in release | | linux-raspi2 | 18.10 cosmic | Not affected | | 18.04 LTS bionic | Fixed 4.15.0-1021.23 | | 17.10 artful | Ignored end of life | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | | linux-snapdragon | 18.10 cosmic | Not in release | | 18.04 LTS bionic | Not affected | | 17.10 artful | Not affected | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) * [Patch details](https://ubuntu.com/security/CVE-2018-12904?format=md#patch-details) ## Notes --- ### [tyhicks](https://launchpad.net/~tyhicks) Ubuntu kernels do not enable nested KVM virtualization by default and are unaffected by this flaw in the default configuration. To ensure that nested virtualization is not enabled, verify that the /sys/module/kvm\_intel/parameters/nested file contains "N". ### Patch details For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) | Package | Patch details | | --- | --- | | linux | * Introduced by [70f3aac](https://git.kernel.org/linus/70f3aac964ae2bc9a0a1d5d65a62e258591ade18), fixed by [727ba74](https://git.kernel.org/linus/727ba748e110b4de50d142edca9d6a9b7e6111d8) | ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 4.9 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Local | | Attack complexity | High | | Privileges required | None | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | Low | | Integrity impact | Low | | Availability impact | Low | * Scores | Parameter | Value | | --- | --- | | Base score | 4.9 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-12904) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-12904) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-12904) * [Debian](https://security-tracker.debian.org/tracker/CVE-2018-12904) ### Related Ubuntu Security Notices (USN) + [USN-3752-2](https://usn.ubuntu.com/USN-3752-2) + Linux kernel (HWE) vulnerabilities + 24 August 2018 + [USN-3752-1](https://usn.ubuntu.com/USN-3752-1) + Linux kernel vulnerabilities + 24 August 2018 + [USN-3752-3](https://usn.ubuntu.com/USN-3752-3) + Linux kernel (Azure, GCP, OEM) vulnerabilities + 28 August 2018 ### Other references * *