Arm CPUs Privilege Escalation Vulnerability Allowing Unauthorized Writes to Higher Exception Level Resources

A vulnerability exists in certain Arm-based CPUs, including the Arm C1-Ultra, C1-Premium, various Neoverse models, and multiple Cortex-A and Cortex-X series processors. This vulnerability may permit unauthorized writes to resources managed by a higher exception level, potentially leading to privilege escalation.

Impact

Exploitation of this vulnerability could allow a lower privilege level to write to resources owned by a higher exception level, potentially leading to unauthorized access or modification of privileged resources.

Remediation

Arm has submitted patches to the Linux Kernel and Trusted Firmware-A to address this vulnerability for affected CPUs. For software performing TLB invalidation related to stage 1 or both stage 1 and 2 information, an additional TLBI and DSB must be executed. Specific details on the required sequence can be found in the erratum for each affected CPU.