Skip to content
Fencer Vulns
medium 5.5

CVE-2016-6828 json

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…

published 2016-10-16 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-7713

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 4.7.2-1

debian advisories DEBIAN-CVE-2016-6828

  • linux Ubuntu 14.04 LTS 3.13.0-98.145
  • linux Ubuntu 16.04 LTS 4.4.0-42.62
  • linux-raspi2 Ubuntu 16.04 LTS 4.4.0-1027.33
  • linux-lts-vivid Ubuntu 14.04 LTS 3.19.0-71.79~14.04.1
  • linux-lts-xenial Ubuntu 14.04 LTS 4.4.0-42.62~14.04.1
  • linux-snapdragon Ubuntu 16.04 LTS 4.4.0-1030.33

ubuntu advisories UBUNTU-CVE-2016-6828

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt enterprise mrg 2 1:3.10.0-514.rt56.210.el6rt
  • kernel-rt-trace enterprise mrg 2 1:3.10.0-514.rt56.210.el6rt
  • kernel-rt-vanilla enterprise mrg 2 1:3.10.0-514.rt56.210.el6rt
  • kernel-rt-firmware enterprise mrg 2 1:3.10.0-514.rt56.210.el6rt
  • kernel-rt-debuginfo-common-x86_64 enterprise mrg 2 1:3.10.0-514.rt56.210.el6rt
  • kernel-rt RHEL 7 EXTRAS_RT 3.10.0-514.6.1.rt56.429.el7
  • kernel-rt-kvm RHEL 7 EXTRAS_RT 3.10.0-514.6.1.rt56.429.el7
  • kernel-rt-trace RHEL 7 EXTRAS_RT 3.10.0-514.6.1.rt56.429.el7

red hat advisories RHSA-2017:0113RHSA-2017:0091RHSA-2017:0086RHSA-2017:0036

  • kernel-ec2 SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1
  • kernel-pae SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3 3.0.101-0.47.96.1
  • kernel-xen SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1
  • kernel-syms SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1
  • kernel-trace SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1
  • kernel-bigsmp SLES 11 SP3-LTSS, OpenStack Cloud 5, Manager Proxy 2.1 +1 more 3.0.101-0.47.96.1
  • kernel-source SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1
  • kernel-default SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 3.0.101-0.47.96.1

suse advisories SUSE-SU-2017:0494-1SUSE-SU-2017:0471-1SUSE-SU-2017:0333-1SUSE-SU-2016:3304-1SUSE-SU-2016:3069-1SUSE-SU-2016:2976-1

  • kernel-source openSUSE Tumbleweed 4.8.13-1.1

opensuse advisories openSUSE-SU-2024:10128-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-6828 updated cvss 4.4

kernel: Use after free in tcp_xmit_retransmit_queue

  • Red Hat Enterprise Linux 5 kernel
    affected: no fix available
  • Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-514.6.1.el7, kernel 3.10.0-514.6.1.el7, python-perf 3.10.0-514.6.1.el7, kernel-tools 3.10.0-514.6.1.el7, kernel-tools-libs 3.10.0-514.6.1.el7, kernel-abi-whitelists 3.10.0-514.6.1.el7, +1 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.6.1.el7 Red Hat Enterprise Linux ComputeNode (v. 7) perf 3.10.0-514.6.1.el7, kernel 3.10.0-514.6.1.el7, python-perf 3.10.0-514.6.1.el7, kernel-tools 3.10.0-514.6.1.el7, kernel-tools-libs 3.10.0-514.6.1.el7, kernel-abi-whitelists 3.10.0-514.6.1.el7, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.6.1.el7
    fixed: vendor fix RHSA-2017:0086
  • Red Hat Enterprise Linux Desktop (v. 6) perf 2.6.32-642.13.1.el6, kernel 2.6.32-642.13.1.el6, kernel-firmware 2.6.32-642.13.1.el6, kernel-abi-whitelists 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6 Red Hat Enterprise Linux Desktop Optional (v. 6) python-perf 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-514.6.1.rt56.429.el7, kernel-rt-kvm 3.10.0-514.6.1.rt56.429.el7, kernel-rt-trace 3.10.0-514.6.1.rt56.429.el7, kernel-rt-debug-kvm 3.10.0-514.6.1.rt56.429.el7, kernel-rt-trace-kvm 3.10.0-514.6.1.rt56.429.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-514.6.1.rt56.429.el7
    fixed: vendor fix RHSA-2017:0091
  • Red Hat Enterprise Linux HPC Node (v. 6) perf 2.6.32-642.13.1.el6, kernel 2.6.32-642.13.1.el6, kernel-firmware 2.6.32-642.13.1.el6, kernel-abi-whitelists 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6 Red Hat Enterprise Linux HPC Node Optional (v. 6) python-perf 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux Realtime (v. 7) kernel-rt 3.10.0-514.6.1.rt56.429.el7, kernel-rt-trace 3.10.0-514.6.1.rt56.429.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-514.6.1.rt56.429.el7
    fixed: vendor fix RHSA-2017:0091
  • Red Hat Enterprise Linux Server (v. 6) perf 2.6.32-642.13.1.el6, kernel 2.6.32-642.13.1.el6, kernel-kdump 2.6.32-642.13.1.el6, kernel-firmware 2.6.32-642.13.1.el6, kernel-bootwrapper 2.6.32-642.13.1.el6, kernel-abi-whitelists 2.6.32-642.13.1.el6, +4 more
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-514.6.1.el7, kernel 3.10.0-514.6.1.el7, python-perf 3.10.0-514.6.1.el7, kernel-kdump 3.10.0-514.6.1.el7, kernel-tools 3.10.0-514.6.1.el7, kernel-tools-libs 3.10.0-514.6.1.el7, +6 more
    fixed: vendor fix RHSA-2017:0086
show 7 more
  • Red Hat Enterprise Linux Server Optional (v. 6) python-perf 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-ppc64 2.6.32-642.13.1.el6, kernel-debuginfo-common-s390x 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-514.6.1.el7, kernel-debuginfo-common-x86_64 3.10.0-514.6.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-514.6.1.el7
    fixed: vendor fix RHSA-2017:0086
  • Red Hat Enterprise Linux Workstation (v. 6) perf 2.6.32-642.13.1.el6, kernel 2.6.32-642.13.1.el6, kernel-firmware 2.6.32-642.13.1.el6, kernel-abi-whitelists 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-514.6.1.el7, kernel 3.10.0-514.6.1.el7, python-perf 3.10.0-514.6.1.el7, kernel-tools 3.10.0-514.6.1.el7, kernel-tools-libs 3.10.0-514.6.1.el7, kernel-abi-whitelists 3.10.0-514.6.1.el7, +1 more
    fixed: vendor fix RHSA-2017:0086
  • Red Hat Enterprise Linux Workstation Optional (v. 6) python-perf 2.6.32-642.13.1.el6, kernel-debuginfo-common-i686 2.6.32-642.13.1.el6, kernel-debuginfo-common-x86_64 2.6.32-642.13.1.el6
    fixed: vendor fix RHSA-2017:0036
  • Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.6.1.el7
    fixed: vendor fix RHSA-2017:0086
  • Red Hat MRG Realtime for RHEL 6 Server v.2 kernel-rt 3.10.0-514.rt56.210.el6rt, kernel-rt-trace 3.10.0-514.rt56.210.el6rt, kernel-rt-vanilla 3.10.0-514.rt56.210.el6rt, kernel-rt-firmware 3.10.0-514.rt56.210.el6rt, kernel-rt-debuginfo-common-x86_64 3.10.0-514.rt56.210.el6rt
    fixed: vendor fix RHSA-2017:0113

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-40731)
  2. Published

Exploit prediction

1.18% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-40731 Linux Kernel - TCP Related Read Use-After-Free dos, 2016-08-18
  • openwall.com http://www.openwall.com/lists/oss-security/2016/08/15/1 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.