In the RISC‑V implementation of the Linux kernel, the function machine_kexec_prepare() copies data from image->segment[i].buf without verifying that the buffer pointer is not NULL. This occurs when ima_add_kexec_buffer() receives a kbuf whose kbuf.buffer field is NULL. The unchecked memcpy therefore dereferences a null pointer, leading to a kernel panic and a denial of service.

Affected systems are all Linux kernel builds that execute the vulnerable riscv machine_kexec_prepare() routine prior to the patch. The specific kernel versions are not listed, so any kernel that has not applied the patch from the referenced Git commits is potentially vulnerable.

The CVSS score of 5.5 indicates moderate severity, and the EPSS score is less than 1%, indicating a low probability of exploitation. The vulnerability is not listed in KEV. Based on the description, it is inferred that a local attacker with the ability to trigger kexec or manipulate the kexec buffer via ima_add_kexec_buffer() could provoke the null dereference. Because the issue requires privileged manipulation of the kexec buffer, the attack vector is likely local with high privilege. The risk is a potential kernel crash, which may allow an attacker to disrupt service or perform privilege escalation if additional conditions are met.