CVE-2026-20503: MediaTek Modem system crash due to missing bounds check
CVE-2026-20503 · Severity: medium · CVSS 5.3 · Published 2026-09-07
MediaTek's modem component, which handles cellular connectivity in smartphones and IoT devices, contains a flaw that allows attackers to crash the system by setting up a rogue base station. An attacker can remotely trigger a denial of service without needing device credentials or user interaction, potentially disrupting communication and device functionality for affected users.
A patch was published on 2026-09-07: Patch ID: MOLY01371002 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-20503 attacked?
It is attacked over the network or from the adjacent network, in device firmware.
Am I affected by CVE-2026-20503?
Check whether you run MediaTek Modem, MediaTek Mt2716, MediaTek Mt2716 Firmware or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A missing bounds check in the MediaTek modem subcomponent allows an out-of-bounds memory access that causes a system crash. The vulnerability can be exploited remotely when a user equipment (UE) connects to an attacker-controlled rogue base station; no additional privileges or user interaction is required. An attacker can achieve a remote denial of service condition. A security patch is available (Patch ID: MOLY01371002).