Remote Yes

Type Denial of service

Description

An integer overflow has been discovered in the Linux kernel when handling TCP Selective Acknowledgments (SACKs). A sequence of SACKs may be crafted such that one can trigger a kernel panic. A remote attacker could use this to cause a denial of service (system crash).

AVG-986 linux-hardened 5.1.10.a-1 5.1.11.a-1 High Vulnerable

AVG-985 linux-zen 5.1.10.zen1-1 5.1.11.zen1-1 High Vulnerable

AVG-983 linux 5.1.9.arch4-1 5.1.11.arch4-1 High Vulnerable

AVG-984 linux-lts 4.19.51-1 4.19.52-1 High Testing

https://www.openwall.com/lists/oss-security/2019/06/17/5
https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-001.md

Workaround:

$ sudo sysctl -w net.ipv4.tcp_sack=0
net.ipv4.tcp_sack = 0

IMPORTANT: The sysctl modification shown above is not persistent across reboots