During initialization of the msc313 RTC driver in the Linux kernel, the probe function requests a shared IRQ but only associates driver data after setting up the clock. If another device sharing the same IRQ line triggers the handler before the driver data is established, the handler uses dev_get_drvdata and obtains a NULL pointer, then dereferences it in interrupt context. This null pointer dereference can crash the kernel, causing a denial of service. The weakness is a classical null pointer dereference (CWE‑476).

The vulnerability affects any Linux kernel that includes the msc313 RTC driver and allows shared IRQ lines. The specific kernel versions are not enumerated in the advisory, so all releases containing the vulnerable probe sequence are potentially impacted.

The CVSS score is not listed in the advisory, and the EPSS score is unavailable, but the bug is exploitable via a concurrent device on the same IRQ line. Since it triggers inside the kernel interrupt context, an attacker with control over another device sharing the IRQ can induce a kernel panic. The vulnerability is not currently reported in CISA KEV. The attack vector is local and requires co‑existence with a device that can trigger the shared IRQ, making it less likely to be broadly exploitable but still serious in embedded or tightly coupled environments.