CVE-2024-53123

A flaw was found in the Linux kernel's Multipath TCP (MPTCP) implementation. Due to improper handling of racing socket disconnect events, the kernel fails to handle error returns appropriately, leading to a division-by-zero error during TCP window calculations. A local attacker can exploit this issue to trigger a system crash, resulting in a denial of service (DoS).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Disable Multipath TCP (MPTCP) protocol support if it is not required:

1. Temporarily disable MPTCP by running:

sysctl -w net.mptcp.enabled=0

2. Persist the configuration across system reboots by creating a sysctl configuration file:

echo "net.mptcp.enabled = 0" > /etc/sysctl.d/99-mptcp.conf

sysctl -p /etc/sysctl.d/99-mptcp.conf

Caveats: Disabling MPTCP will prevent applications from establishing MPTCP connections, causing them to fall back to standard TCP or fail if MPTCP is explicitly required. Applying this configuration takes effect immediately without requiring a system reboot. If unprivileged user namespaces are permitted, unprivileged users may still be able to create new network namespaces with MPTCP enabled.