CVE-2026-20539: CWE-126 Buffer Over-read in MediaTek, Inc. MediaTek chipset

The vulnerability identified as CVE-2026-20539 involves a buffer over-read (CWE-126) in the modem of MediaTek chipsets due to a missing bounds check. An attacker operating a rogue base station can trigger this out-of-bounds read remotely, leading to a denial of service condition on connected UE devices. No user interaction or elevated privileges are necessary for exploitation. The issue is tracked under MediaTek's internal ID MSV-8913 and patch ID MOLY01774038, though no public patch link is provided.

Successful exploitation results in a remote denial of service on affected devices connected to a malicious base station. This disrupts normal device operation but does not grant the attacker additional execution privileges or direct control over the device.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vendor has assigned a patch ID (MOLY01774038) indicating a fix may exist internally, but no public patch or advisory is currently available. Users and administrators should monitor MediaTek advisories for official updates and apply patches once released.