--- title: "CVE-2015-4177\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-2015-4177?format=md keywords: index, follow --- # CVE-2015-4177 Publication date 2 May 2016 Last updated 4 July 2026 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **5.5 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2015-4177?format=md#impact-score) Toggle side navigation ## Description The collect\_mounts function in fs/namespace.c in the Linux kernel before 4.0.5 does not properly consider that it may execute after a path has been unmounted, which allows local users to cause a denial of service (system crash) by leveraging user-namespace root access for an MNT\_DETACH umount2 system call. [Read the notes from the security team](https://ubuntu.com/security/CVE-2015-4177?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | linux | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not affected | | 15.10 wily | Not affected | | 15.04 vivid | Not affected | | 14.10 utopic | Not affected | | 14.04 LTS trusty | Not affected | | 12.04 LTS precise | Not affected | | linux-2.6 | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-armadaxp | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | 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-ec2 | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 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 | | 15.04 vivid | Not affected | | 14.10 utopic | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-fsl-imx51 | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 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 | | 15.04 vivid | Not affected | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | Ignored end of life | | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | | linux-lts-raring | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life, was needs-triage | | linux-lts-saucy | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | | linux-lts-trusty | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 14.04 LTS trusty | Not in release | | 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 | | 15.04 vivid | 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 | | 15.04 vivid | Not in release | | 14.04 LTS trusty | Not affected | | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | | 15.04 vivid | Not affected | | 14.10 utopic | 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 | | 15.04 vivid | Not affected | | 14.10 utopic | Not affected | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-mvl-dove | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 15.10 wily | Not in release | | 15.04 vivid | Not in release | | 14.10 utopic | Not in release | | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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 | Not affected | | 15.10 wily | Not affected | | 15.04 vivid | Not in release | | 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 | Not affected | | 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 | | 15.04 vivid | Not in release | | 14.10 utopic | 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-2015-4177?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 [ce07d89](https://git.kernel.org/linus/ce07d891a0891d3c0d0c2d73d577490486b809e1), fixed by [cd4a401](https://git.kernel.org/linus/cd4a40174b71acd021877341684d8bb1dc8ea4ae) | ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 5.5 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Local | | Attack complexity | Low | | Privileges required | Low | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | None | | Integrity impact | None | | Availability impact | High | * Scores | Parameter | Value | | --- | --- | | Base score | 5.5 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4177) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2015-4177) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2015-4177) * [Debian](https://security-tracker.debian.org/tracker/CVE-2015-4177) ### Other references * * *