CVE-2016-6828

Severity: medium (CVSS 5.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2016-10-16 · updated 2026-06-17
Weakness: CWE-416

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.

Affected products

Linux kernel: through 4.7.4

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bb1fceca22492109be12640d49f5ea5a544c6bb4
http://rhn.redhat.com/errata/RHSA-2017-0036.html
http://rhn.redhat.com/errata/RHSA-2017-0086.html
http://rhn.redhat.com/errata/RHSA-2017-0091.html
http://rhn.redhat.com/errata/RHSA-2017-0113.html
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.7.5
http://www.openwall.com/lists/oss-security/2016/08/15/1
http://www.securityfocus.com/bid/92452
https://bugzilla.redhat.com/show_bug.cgi?id=1367091
https://github.com/torvalds/linux/commit/bb1fceca22492109be12640d49f5ea5a544c6bb4
https://marcograss.github.io/security/linux/2016/08/18/cve-2016-6828-linux-kernel-tcp-uaf.html
https://source.android.com/security/bulletin/2016-11-01.html

Get alerted when CVE-2016-6828 or the next vulnerability affects your stack