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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 4.7.2-1 | — |
| Debian 13 | linux | 4.7.2-1 | — |
| Debian 12 | linux | 4.7.2-1 | — |
| Debian 8 | linux | 3.16.36-1+deb8u1 | DSA-3659-1 |
| Debian 7 | linux | 3.2.81-2 | DLA-609-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux | 4.4.0-42.62 | USN-3099-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1027.33 | USN-3099-3 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1030.33 | USN-3099-4 |
| Ubuntu 14.04 LTS | linux | 3.13.0-98.145 | USN-3098-1 |
| Ubuntu 14.04 LTS | linux-lts-vivid | 3.19.0-71.79~14.04.1 | — |
| Ubuntu 14.04 LTS | linux-lts-xenial | 4.4.0-42.62~14.04.1 | USN-3099-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | kernel-rt +10 | 3.10.0-514.6.1.rt56.429.el7 | RHSA-2017:0091 |
| RHEL 7 | perf +18 | 3.10.0-514.6.1.el7 | RHSA-2017:0086 |
| RHEL 6 | perf +16 | 2.6.32-642.13.1.el6 | RHSA-2017:0036 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat MRG 2 | kernel-rt +10 | 1:3.10.0-514.rt56.210.el6rt | RHSA-2017:0113 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | kernel-docs | 3.12.67-60.64.18.3 | SUSE-SU-2016:2912-1 |
| SLES 12 SP1 | kernel-xen +4 | 3.12.67-60.64.18.1 | SUSE-SU-2016:2912-1 |
| SLES 12 | kernel-ec2 +4 | 3.12.61-52.66.1 | SUSE-SU-2017:0471-1, SUSE-SU-2016:2912-1 |
| SLES 12 | kgraft-patch-SLE12_Update_19 | 1-2.1 | SUSE-SU-2017:0471-1 |
| SLES 11 SP4 | kernel-docs | 3.0.101-88.3 | SUSE-SU-2016:2976-1 |
| SLES 11 SP4 | kernel-ec2 +8 | 3.0.101-88.1 | SUSE-SU-2016:2976-1 |
| SLES 11 SP3 | kernel-ec2 +7 | 3.0.101-0.47.96.1 | SUSE-SU-2017:0494-1 |
| SLES 11 SP2 | kernel-ec2 +6 | 3.0.101-0.7.53.1 | SUSE-SU-2017:0333-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | kernel-xen +3 | 3.12.67-60.64.18.1 | SUSE-SU-2016:2912-1 |
| SLES for SAP 12 | kernel-xen +3 | 3.12.61-52.66.1 | SUSE-SU-2017:0471-1 |
| SLES for SAP 12 | kgraft-patch-SLE12_Update_19 | 1-2.1 | SUSE-SU-2017:0471-1 |
| SLES for SAP 11 SP4 | kernel-ec2 +8 | 3.0.101-88.1 | SUSE-SU-2016:2976-1 |
| SLE Real Time 12 SP1 | kernel-rt +5 | 3.12.67-60.27.1 | SUSE-SU-2016:3304-1 |
| SLE Real Time 11 SP4 | kernel-rt +3 | 3.0.101.rt130-65.1 | SUSE-SU-2016:3069-1 |
| SLE Live Patching 12 | kgraft-patch-SLE12-SP1_Update_9 | 1-6.3 | SUSE-SU-2016:2912-1 |
| SUSE OpenStack Cloud 5 | kernel-ec2 +6 | 3.0.101-0.47.96.1 | SUSE-SU-2017:0494-1 |
| SUSE Manager Proxy 2.1 | kernel-ec2 +6 | 3.0.101-0.47.96.1 | SUSE-SU-2017:0494-1 |
| SUSE Manager 2.1 | kernel-ec2 +6 | 3.0.101-0.47.96.1 | SUSE-SU-2017:0494-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | kernel-ec2 +6 | 3.0.101-0.47.96.1 | SUSE-SU-2017:0494-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 4.8.13-1.1 | openSUSE-SU-2024:10128-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | dtrace-modules-3.8.13-118.16.2.el6uek | 0.4.5-3.el6 | ELSA-2017-3509 |
| Oracle Linux 7 | dtrace-modules-3.8.13-118.16.2.el7uek | 0.4.5-3.el7 | ELSA-2017-3509 |
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.25.el6uek | 0.5.3-2.el6 | ELSA-2017-3508 |
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.25.el7uek | 0.5.3-2.el7 | ELSA-2017-3508 |
| Oracle Linux 7 | kernel-uek +5 | 3.8.13-118.16.2.el7uek | ELSA-2017-3509, ELSA-2017-3508 |
| Oracle Linux 7 | perf +11 | 3.10.0-514.6.1.el7 | ELSA-2017-0086 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Linux Kernel - TCP Related Read Use-After-Free EDB-40731 · dos · Aug 18, 2016
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 22
- RHSA-2017:0113 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2017:0086 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2017:0091 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2017:0036 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- USN-3099-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3098-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-609-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3659-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3099-2 linux-lts-xenial vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3099-3 linux-raspi2 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3099-4 linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2016:2976-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0494-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10128-1 kernel-debug-4.8.13-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0471-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:3069-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0333-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2912-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:3304-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2017-0086 Important: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 17, 2017
- ELSA-2017-3509 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2017
- ELSA-2017-3508 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2017
References
- https://github.com/torvalds/linux/commit/bb1fceca22492109be12640d49f5ea5a544c6bb4
- RHSA-2017:0086 vendor-advisory
- RHSA-2017:0113 vendor-advisory
- RHSA-2017:0091 vendor-advisory
- [oss-security] 20160815 Linux tcp_xmit_retransmit_queue use after free on 4.8-rc1 / master mailing-list
- 92452 vdb-entry
- https://source.android.com/security/bulletin/2016-11-01.html
- RHSA-2017:0036 vendor-advisory
- https://marcograss.github.io/security/linux/2016/08/18/cve-2016-6828-linux-kernel-tcp-uaf.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1367091
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.7.5
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bb1fceca22492109be12640d49f5ea5a544c6bb4