--- title: "CVE-2016-6828\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-2016-6828?format=md keywords: index, follow --- # CVE-2016-6828 Publication date 18 August 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-2016-6828?format=md#impact-score) Toggle side navigation ## Description The tcp\_check\_send\_head function in include/net/tcp.h in the Linux kernel before 4.7.5 does not properly maintain certain SACK state after a failed data copy, which allows local users to cause a denial of service (tcp\_xmit\_retransmit\_queue use-after-free and system crash) via a crafted SACK option. ### From the Ubuntu Security Team Marco Grassi discovered a use-after-free condition could occur in the TCP retransmit queue handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. [Read the notes from the security team](https://ubuntu.com/security/CVE-2016-6828?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | linux | 17.04 zesty | Not affected | | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-42.62 | | 14.04 LTS trusty | Fixed 3.13.0-98.145 | | 12.04 LTS precise | Fixed 3.2.0-111.153 | | 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 | Fixed 3.2.0-1674.100 | | linux-aws | 17.04 zesty | Not in release | | 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 | 17.04 zesty | Not in release | | 16.10 yakkety | Ignored end of life | | 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 | Ignored end of life | | 16.10 yakkety | Ignored end of life | | 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 3.13.0-98.145~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 3.19.0-71.79~14.04.1 | | 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 4.4.0-42.62~14.04.1 | | 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 | Ignored end of life | | 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 | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-1027.33 | | 14.04 LTS trusty | Not in release | | 12.04 LTS precise | Not in release | | linux-snapdragon | 17.04 zesty | Not affected | | 16.10 yakkety | Not affected | | 16.04 LTS xenial | Fixed 4.4.0-1030.33 | | 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 | Fixed 3.2.0-1489.116 | --- * [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-2016-6828?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 [6859d49](https://git.kernel.org/linus/6859d49475d4f32abe640372117e4b687906e6b6), fixed by [bb1fcec](https://git.kernel.org/linus/bb1fceca22492109be12640d49f5ea5a544c6bb4) | ## 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-2016-6828) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-6828) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-6828) * [Debian](https://security-tracker.debian.org/tracker/CVE-2016-6828) ### Related Ubuntu Security Notices (USN) + [USN-3099-3](https://usn.ubuntu.com/USN-3099-3) + Linux kernel (Raspberry Pi 2) vulnerabilities + 11 October 2016 + [USN-3099-1](https://usn.ubuntu.com/USN-3099-1) + Linux kernel vulnerabilities + 11 October 2016 + [USN-3097-2](https://usn.ubuntu.com/USN-3097-2) + Linux kernel (OMAP4) vulnerabilities + 13 October 2016 + [USN-3099-4](https://usn.ubuntu.com/USN-3099-4) + Linux kernel (Qualcomm Snapdragon) vulnerabilities + 11 October 2016 + [USN-3099-2](https://usn.ubuntu.com/USN-3099-2) + Linux kernel (Xenial HWE) vulnerabilities + 11 October 2016 + [USN-3097-1](https://usn.ubuntu.com/USN-3097-1) + Linux kernel vulnerabilities + 11 October 2016 + [USN-3098-2](https://usn.ubuntu.com/USN-3098-2) + Linux kernel (Trusty HWE) vulnerabilities + 11 October 2016 + [USN-3098-1](https://usn.ubuntu.com/USN-3098-1) + Linux kernel vulnerabilities + 11 October 2016 ### Other references * *