The Linux kernel contains a defect in the DMA engine Axi‑DMAC implementation where a call to dma_free_coherent() can occur from a softirq context. Because the DMA channel uses DMA_DIRECT_REMAP, the allocated memory may live under vmalloc and freeing it in interrupt context triggers a vunmap() from a softirq, which is forbidden and causes a BUG() in the kernel. This defect can lead to a kernel panic or system crash if the DMA channel is exercised while the faulting condition exists.

The bug is limited to Linux kernel configurations that enable the Axi‑DMAC driver on architectures such as Microblaze or arm64 where DMA_DIRECT_REMAP is active. No specific kernel version range is listed, so any build containing the affected driver code for those architectures is potentially vulnerable.

The CVSS score for this issue is not supplied in the current data set, but the EPSS score of 0.00209 indicates a very low probability of exploitation. Because the defect causes a kernel panic, it represents a high availability impact. The bug would only be triggered when the DMA engine is used under the specific scenario described, so the likelihood of exploitation without privileged local or remote access is low. The vulnerability is not listed in the CISA KEV catalogue, indicating that it is not a known actively exploited vulnerability at the time of this analysis.