--- title: "CVE-2016-4794\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-2016-4794?format=md keywords: index, follow --- # CVE-2016-4794 Publication date 23 May 2016 Last updated 4 July 2026 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **7.8 · High** [Score breakdown](https://ubuntu.com/security/CVE-2016-4794?format=md#impact-score) Toggle side navigation ## Description Use-after-free vulnerability in mm/percpu.c in the Linux kernel through 4.6 allows local users to cause a denial of service (BUG) or possibly have unspecified other impact via crafted use of the mmap and bpf system calls. ### From the Ubuntu Security Team Sasha Levin discovered that a use-after-free existed in the percpu allocator in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges. [Read the notes from the security team](https://ubuntu.com/security/CVE-2016-4794?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | linux | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-34.53 | | 15.10 wily | Ignored end of life | | 14.04 LTS trusty | Not affected | | 12.04 LTS precise | Not affected | | linux-armadaxp | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | | linux-aws | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not affected | | 12.04 LTS precise | Not in release | | linux-flo | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-gke | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-goldfish | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-grouper | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-hwe | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-hwe-edge | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-linaro-omap | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-linaro-shared | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-linaro-vexpress | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-quantal | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-raring | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-saucy | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-trusty | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | | linux-lts-utopic | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-lts-vivid | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Fixed 3.19.0-66.74~14.04.1 | | 12.04 LTS precise | Not in release | | linux-lts-wily | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-lts-xenial | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Fixed 4.4.0-34.53~14.04.1 | | 12.04 LTS precise | Not in release | | linux-maguro | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-mako | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-manta | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-qcm-msm | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-raspi2 | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-1019.25 | | 15.10 wily | Ignored end of life | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-snapdragon | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-1022.25 | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-ti-omap4 | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | --- * [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-2016-4794?format=md#patch-details) ## Notes --- ### [jdstrand](https://launchpad.net/~jdstrand) android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support ### 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 [9c824b6](https://git.kernel.org/linus/9c824b6a172c8d44a6b037946bae90127c969b1b), fixed by [4f996e2](https://git.kernel.org/linus/4f996e234dad488e5d9ba0858bc1bae12eff82c3) * Introduced by [1a4d760](https://git.kernel.org/linus/1a4d76076cda69b0abf15463a8cebc172406da25), fixed by [6710e59](https://git.kernel.org/linus/6710e594f71ccaad8101bc64321152af7cd9ea28) | ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 7.8 · High * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Local | | Attack complexity | Low | | Privileges required | Low | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | High | | Integrity impact | High | | Availability impact | High | * Scores | Parameter | Value | | --- | --- | | Base score | 7.8 · High | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-4794) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-4794) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-4794) * [Debian](https://security-tracker.debian.org/tracker/CVE-2016-4794) ### Related Ubuntu Security Notices (USN) + [USN-3057-1](https://usn.ubuntu.com/USN-3057-1) + Linux kernel (Qualcomm Snapdragon) vulnerabilities + 10 August 2016 + [USN-3054-1](https://usn.ubuntu.com/USN-3054-1) + Linux kernel (Xenial HWE) vulnerabilities + 10 August 2016 + [USN-3056-1](https://usn.ubuntu.com/USN-3056-1) + Linux kernel (Raspberry Pi 2) vulnerabilities + 10 August 2016 + [USN-3053-1](https://usn.ubuntu.com/USN-3053-1) + Linux kernel (Vivid HWE) vulnerabilities + 10 August 2016 + [USN-3055-1](https://usn.ubuntu.com/USN-3055-1) + Linux kernel vulnerabilities + 10 August 2016 ### Other references *