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.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://github.com/torvalds/linux/commit/bb1fceca22492109be12640d49f5ea5a544c6bb4 | issue tracking patch |
| http://rhn.redhat.com/errata/RHSA-2017-0086.html | vendor advisory |
| http://rhn.redhat.com/errata/RHSA-2017-0113.html | vendor advisory |
| http://rhn.redhat.com/errata/RHSA-2017-0091.html | vendor advisory |
| http://www.openwall.com/lists/oss-security/2016/08/15/1 | mailing list exploit third party advisory |
| http://www.securityfocus.com/bid/92452 | vdb entry |
| https://source.android.com/security/bulletin/2016-11-01.html | |
| http://rhn.redhat.com/errata/RHSA-2017-0036.html | 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 | issue tracking third party advisory |
| http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.7.5 | third party advisory release notes |
| http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bb1fceca22492109be12640d49f5ea5a544c6bb4 | issue tracking patch |