A flaw was reported in kernel TCP subsystem while calculating a packet round trip time, when a sysctl parameter (/proc/sys/net/ipv4/tcp_min_rtt_wlen) when is set wrongly. This causes an integer over flaw which can lead to a Denial Of Service (DOS) attack. Additional Information: ----------------------- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19fad20d15a6494f47f85d869f00b11343ee5c78
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1771498]
This was fixed for Fedora with the 5.0.11 stable kernel updates.
Mitigation: This flaw can be mitigated by setting the sysctl parameter (/proc/sys/net/ipv4/tcp_min_rtt_wlen) with 300 which means the packet time will not exceed more then 5 minutes and which should not cause an integer overflow.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:0740 https://access.redhat.com/errata/RHSA-2020:0740
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2019-18805
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:1567 https://access.redhat.com/errata/RHSA-2020:1567
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:1769 https://access.redhat.com/errata/RHSA-2020:1769