--- title: "CVE-2016-9793\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-2016-9793?format=md keywords: index, follow --- # CVE-2016-9793 Publication date 28 December 2016 Last updated 4 July 2026 --- Ubuntu priority **Low** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **7.8 · High** [Score breakdown](https://ubuntu.com/security/CVE-2016-9793?format=md#impact-score) Toggle side navigation ## Description The sock\_setsockopt function in net/core/sock.c in the Linux kernel before 4.8.14 mishandles negative values of sk\_sndbuf and sk\_rcvbuf, which allows local users to cause a denial of service (memory corruption and system crash) or possibly have unspecified other impact by leveraging the CAP\_NET\_ADMIN capability for a crafted setsockopt system call with the (1) SO\_SNDBUFFORCE or (2) SO\_RCVBUFFORCE option. ### From the Ubuntu Security Team Andrey Konovalov discovered that signed integer overflows existed in the setsockopt() system call when handling the SO\_SNDBUFFORCE and SO\_RCVBUFFORCE options. A local attacker with the CAP\_NET\_ADMIN capability could use this to cause a denial of service (system crash or memory corruption). [Read the notes from the security team](https://ubuntu.com/security/CVE-2016-9793?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | linux | 17.04 zesty | Not affected | | 16.10 yakkety | Fixed 4.8.0-34.36 | | 16.04 LTS xenial | Fixed 4.4.0-59.80 | | 14.04 LTS trusty | Fixed 3.13.0-107.154 | | 12.04 LTS precise | Not affected | | linux-armadaxp | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not affected | | linux-aws | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Fixed 4.4.0-1003.12 | | 14.04 LTS trusty | Not affected | | 12.04 LTS precise | Not in release | | linux-flo | 17.04 zesty | Not in release | | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-gke | 17.04 zesty | Not in release | | 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 | 17.04 zesty | Not affected | | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-grouper | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-hwe | 17.04 zesty | Not in release | | 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 | 17.04 zesty | Not in release | | 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 | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-linaro-shared | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-linaro-vexpress | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-quantal | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-raring | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-saucy | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-lts-trusty | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Fixed 3.13.0-107.154~precise1 | | linux-lts-utopic | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-lts-vivid | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Fixed 3.19.0-79.87~14.04.1 | | 12.04 LTS precise | Not in release | | linux-lts-wily | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-lts-xenial | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Fixed 4.4.0-59.80~14.04.1 | | 12.04 LTS precise | Not in release | | linux-maguro | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-mako | 17.04 zesty | Not in release | | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-manta | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-qcm-msm | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | Not in release | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Ignored end of life | | linux-raspi2 | 17.04 zesty | Not affected | | 16.10 yakkety | Fixed 4.8.0-1022.25 | | 16.04 LTS xenial | Fixed 4.4.0-1040.47 | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-snapdragon | 17.04 zesty | Not affected | | 16.10 yakkety | Fixed 4.4.0-1046.50 | | 16.04 LTS xenial | Fixed 4.4.0-1044.48 | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-ti-omap4 | 17.04 zesty | Not in release | | 16.10 yakkety | Not in release | | 16.04 LTS xenial | 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-2016-9793?format=md#patch-details) ## Notes --- ### [sbeattie](https://launchpad.net/~sbeattie) the overflows exist for SO\_{SND|RCV}BUFFORCE, so it's possible for a process with CAP\_NET\_ADMIN to do this. However, the check for CAP\_NET\_ADMIN is via capable() \*not\* ns\_capable(), so the process attempting this has to have CAP\_NET\_ADMIN in the init\_ns; having it in a new user namespace (i.e. via unshare()) is not sufficient. Thus, this cannot be exploited by an unprivileged user dropping into an unprivileged user namespace. Hence the low priority. ### 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 [8298193](https://git.kernel.org/linus/82981930125abfd39d7c8378a9cfdf5e1be2002b), fixed by [b98b0bc](https://git.kernel.org/linus/b98b0bc8c431e3ceb4b26b0dfc8db509518fb290) | ## 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-2016-9793) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-9793) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-9793) * [Debian](https://security-tracker.debian.org/tracker/CVE-2016-9793) ### Related Ubuntu Security Notices (USN) + [USN-3169-3](https://usn.ubuntu.com/USN-3169-3) + Linux kernel (Raspberry Pi 2) vulnerabilities + 11 January 2017 + [USN-3168-2](https://usn.ubuntu.com/USN-3168-2) + Linux kernel (Trusty HWE) vulnerabilities + 11 January 2017 + [USN-3168-1](https://usn.ubuntu.com/USN-3168-1) + Linux kernel vulnerabilities + 11 January 2017 + [USN-3169-2](https://usn.ubuntu.com/USN-3169-2) + Linux kernel (Xenial HWE) vulnerabilities + 11 January 2017 + [USN-3169-1](https://usn.ubuntu.com/USN-3169-1) + Linux kernel vulnerabilities + 11 January 2017 + [USN-3169-4](https://usn.ubuntu.com/USN-3169-4) + Linux kernel (Qualcomm Snapdragon) vulnerabilities + 11 January 2017 + [USN-3170-2](https://usn.ubuntu.com/USN-3170-2) + Linux kernel (Raspberry Pi 2) vulnerabilities + 11 January 2017 + [USN-3170-1](https://usn.ubuntu.com/USN-3170-1) + Linux kernel vulnerabilities + 11 January 2017 ### Other references * * *