CVE-2025-20727 is a heap buffer overflow vulnerability classified under CWE-787 found in the modem firmware of a wide range of MediaTek chipsets, including models MT2735 through MT8893. The vulnerability arises due to an out-of-bounds write condition in the modem software, which can be triggered remotely when a user equipment (UE) connects to a maliciously controlled rogue base station. This flaw does not require any user interaction or prior authentication, making it highly exploitable in real-world scenarios. The attacker can leverage this vulnerability to escalate privileges remotely within the modem subsystem, potentially gaining control over modem operations or executing arbitrary code. The modem versions affected include LR12A, NR15, NR16, NR17, and NR17R. The CVSS v3.1 base score is 8.1, reflecting high severity with network attack vector, high impact on confidentiality, integrity, and availability, and no privileges or user interaction required. The vulnerability was publicly disclosed on November 4, 2025, with MediaTek assigning the patch ID MOLY01672601 and issue ID MSV-4623. No public exploits have been reported yet, but the extensive list of affected chipsets suggests a large attack surface across many mobile devices globally. The vulnerability could allow attackers to compromise the modem’s security functions, potentially affecting device communications and user data privacy.

The impact of CVE-2025-20727 is significant for organizations and end-users relying on mobile devices powered by affected MediaTek chipsets. Successful exploitation can lead to remote privilege escalation within the modem, enabling attackers to manipulate modem firmware, intercept or alter communications, or disrupt network connectivity. This undermines the confidentiality, integrity, and availability of mobile communications, potentially exposing sensitive data or enabling further attacks on the device or network. Enterprises with mobile workforces, telecom operators, and IoT deployments using these chipsets face increased risk of targeted attacks or widespread compromise if rogue base stations are deployed. The vulnerability could also facilitate espionage or surveillance by adversaries controlling rogue base stations. Given the broad chipset coverage, the threat extends to millions of consumer and industrial devices worldwide, impacting mobile security and trust in wireless communications.

To mitigate CVE-2025-20727, organizations and device manufacturers should prioritize applying the official patches released by MediaTek (Patch ID: MOLY01672601). Mobile device vendors must ensure firmware updates incorporating these patches are distributed promptly to end-users. Network operators should monitor for and mitigate rogue base stations within their coverage areas using advanced detection and blocking techniques. Device users should keep their devices updated with the latest firmware and security patches. Additionally, implementing network-level protections such as base station authentication and anomaly detection can reduce exposure to rogue base station attacks. Security teams should conduct risk assessments on devices using affected chipsets and consider network segmentation or additional endpoint protections to limit potential damage. Collaboration between telecom providers, device manufacturers, and security researchers is essential to detect exploitation attempts and develop further defensive measures.