UBUNTU-CVE-2026-89740: Low severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: serial: imx: serialize imxuartports[] lifetime imxuartprobe() publishes its devm-allocated port in imxuartports[] before uartaddoneport() because console setup uses the table. The entry is not cleared when adding the port fails or after removal, leaving a dangling pointer. A sibling probe can register the shared console through that stale entry. This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART and rebinding the sibling. Keep the entry valid through uartremoveoneport(), then clear it. Protect port addition and removal together with their table updates so sibling operations cannot interleave. Reject an occupied slot rather than clobbering an active port during a duplicate-line probe.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
Serialize UART port addition and removal together with updates to imx_uart_ports[], keep each table entry valid through uart_remove_one_port(), and clear the entry after removal or when uart_add_one_port() fails.
- Compensating control
Reject a duplicate-line probe when the corresponding imx_uart_ports[] slot is already occupied instead of overwriting the active port.
Event History
Frequently Asked Questions
Which Ubuntu kernel package variants are identified in the advisory?
The advisory lists ubuntu/linux, ubuntu/linux-fips, ubuntu/linux-aws, ubuntu/linux-aws-fips, ubuntu/linux-azure, ubuntu/linux-azure-fips, ubuntu/linux-gcp, and ubuntu/linux-gcp-fips. No affected or fixed package versions are provided.
What device-management activity is associated with reproducing the issue?
The issue was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART, and then rebinding the sibling UART. The documented scenario involves i.MX UART devices and a shared console registration using a stale port-table entry.
What should the corrected driver behavior prevent?
The port-table entry should remain valid until uart_remove_one_port() completes and then be cleared. Port addition and removal must be serialized with table updates, and a duplicate-line probe must reject an occupied slot instead of overwriting an active port.