The vulnerability occurs in the Linux kernel's irqchip/crossbar code, where the free operation mistakenly uses a nulled irq_data->hwirq as an index when clearing the IRQ mapping. This results in the wrong crossbar register being reset and the associated IRQ remaining logically active. The bug allows an attacker to leave interrupt mappings lingering or to overwrite other entries by targeting out‑of‑bounds indices, which could lead to incorrect interrupt handling, kernel crashes, or denial of service.

Affected systems are all Linux kernel distributions that include the irqchip/crossbar implementation. No specific kernel versions are listed in the advisory, so any distribution that uses the default kernel configuration with irqchip/crossbar enabled may be impacted.

The advisory now lists a CVSS score of 5.5 and a very low EPSS of < 1%, and it is not listed in the CISA KEV. The exploit requires an attacker to trigger a crossbar domain free operation in the kernel, typically through a malicious driver or a privileged user. If successfully carried out, the mis‑indexed reset can cause resource leaks and potential out‑of‑bounds memory accesses. Given the local nature and lack of a public exploit, the risk is considered moderate; a patched kernel eliminates the possibility of denial of service, resource leaks, and out‑of‑bounds memory accesses.