In the Linux kernel, the TCP receive window calculation assumes a minimum segment size (MSS) greater than zero. A route-derived advertised MSS (RTAX_ADVMSS) can be zero or smaller than the minimum, causing a division by zero in tcp_select_initial_window(). When this occurs, the kernel may crash or panic, resulting in a denial of service to the affected host. The vulnerability stems from an unchecked assumption and can be exploited by manipulating routing parameters that influence the advertised MSS.

All Linux kernel versions that lack the recent patch fixing the MSS clamping bug are affected. The issue was addressed in the commit referenced by the provided links and applies to any kernel releasing before that point. System administrators using older kernels should verify whether their builds contain the fix or plan an update accordingly.

The CVSS score is not provided, but the potential for a kernel panic and the nature of the divide‑by‑zero flaw suggest a critical severity if exploited. Without an EPSS metric, the likelihood of attack is uncertain, yet the absence of KEV listing does not preclude future exploitation. Monitoring for kernel panics and promptly applying the patch mitigates the threat explorer.