> CVE-2021-32484: Heap Buffer overflow in GSM RRM E-UTRAN Individual Priority Parameters

Summary In this advisory we are disclosing a heap overflow vulnerability in the MediaTek baseband. The vulnerability can be exploited to gain arbitrary code execution in the context of the baseband runtime. The vulnerability was fixed in 2020 in some models, and received a CVE and more widely deployed fix in 2021. Vulnerability Details When processing the CSN.1 decoding of the “E-UTRAN Individual Priority Parameters” element, the function rr_decode_eutran_individual_priority_para_description implements a two-depth nested repetition (Repeated Individual E-UTRAN Priority Parameters Description struct and its child element EARFCN). The outer loop is iterated by checking on the single bit representing the ongoing repetition, and while that equals “1”, a new Repeated Individual E-UTRAN Priority Parameters Description struct is processed.