CVE-2016-6828
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Exploit-DB
Linux Kernel - TCP Related Read Use-After-Free
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 4.7.2-1 |
| debian | bullseye | fixed | 4.7.2-1 |
| debian | forky | fixed | 4.7.2-1 |
| debian | sid | fixed | 4.7.2-1 |
| debian | trixie | fixed | 4.7.2-1 |
| linux-kernel | affected | |
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
- https://www.suse.com/security/cve/CVE-2016-6828.html
- https://security-tracker.debian.org/tracker/CVE-2016-6828
CWEs
CWE-416
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.