The vulnerability exists in the Linux kernel’s traffic‑control module, specifically the cls_flow subsystem. When a flow filter is created on a shared block whose queue pointer is null, a function dereferences the handle of a null queue, resulting in a kernel panic. This is a pure crash condition that can cause the system to become unusable, but it does not allow execution of arbitrary code or compromise of data.

Any system running a Linux kernel that includes the vulnerable cls_flow implementation and has not yet incorporated the patch adding a null‑check on shared blocks is affected. The vulnerability resides in the core kernel, so it applies to all distributions that ship the unpatched kernel source. Specific version identifiers are not listed in the data, but any kernel version preceding the commit that adds the check should be considered vulnerable.

The CVSS score of 4.7 classifies the severity as moderate. An EPSS value is not available, and the flaw is not listed in CISA’s KEV catalog, indicating no widespread confirmed exploitation. The data describes the kernel panic trigger but does not specify how to reach the vulnerable code. Based on the description, it is inferred that an attacker could need to send a specially crafted netlink message to the networking stack to create the problematic flow filter. However, the exact privilege level required (e.g., root, CAP_NET_ADMIN) is not directly stated in the available information. Consequently, the overall risk is moderate for hosts where an attacker can attain necessary privileges or influence networking configurations, while it is lower for environments lacking such access.