CVE-2023-54287: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54287 is a Linux kernel vulnerability in the i.MX UART serial driver (tty: serial: imx) that causes a kernel panic due to a NULL pointer dereference. The issue arises when a pending USR (Ageing Timer) interrupt fires before uart_add_one_port has completed initialization, leading to a crash at virtual address 0x0000000000000080. The vulnerability specifically manifests on Freescale i.MX8MP hardware running as an inmate Linux instance under the Jailhouse hypervisor. It was published to NVD on December 30, 2025, and carries an estimated CVSS severity of Medium with an EPSS score of 0.000250 (Feedly, VulDB).

The root cause is a race condition (CWE-362) in the i.MX UART driver's interrupt handling: a pending Ageing Timer (USR) interrupt can be delivered before the port structure is fully initialized by uart_add_one_port, causing __imx_uart_rxint to dereference a NULL pointer at offset 0x80. The crash trace shows the fault occurring in __imx_uart_rxint.constprop.0+0x11c/0x2c0 called from imx_uart_int+0xf8/0x1ec. The fix involves disabling the Ageing Timer interrupt request (IRQ) prior to registering the IRQ handler, ensuring no interrupt can fire against an uninitialized port. Patches are available in the stable kernel tree at commits 3d41d9b256ae, 9795ece3a85b, 963875b06551, and ef25e16ea967 (Feedly, kernel.org patch 1).

Successful triggering of this vulnerability results in a kernel panic (system crash), causing a complete loss of availability for the affected Linux instance. Because the crash occurs during boot initialization under the Jailhouse hypervisor, it can prevent the inmate Linux cell from starting at all, disrupting embedded or real-time workloads on i.MX8MP-based platforms. There is no evidence of confidentiality or integrity impact; the vulnerability is limited to a denial-of-service condition (Feedly).

Apply the upstream Linux kernel patches that disable the Ageing Timer IRQ before requesting the interrupt handler in the i.MX UART driver. The fixes are available in the stable kernel tree at commits 3d41d9b256ae626c0dc434427c8e32450358d3b4, 9795ece3a85ba9238191e97665586e2d79703ff3, 963875b0655197281775b0ea614aab8b6b3eb001, and ef25e16ea9674b713a68c3bda821556ce9901254. As a workaround, avoid repeatedly enabling and disabling Jailhouse inmate Linux cells on affected i.MX8MP hardware until a patched kernel is deployed (Feedly).