CVE-2026-20525

CVE-2026-20525 is a reachable-assertion flaw (CWE-617) in the MediaTek modem caused by improper input validation. A remote attacker who operates a rogue base station can crash the modem, and therefore the user equipment, after the device connects to that station; no extra privileges and no user interaction are required. The result is a remote denial of service, not code execution. MediaTek tracks the fix as patches MOLY01870473 and MOLY00814393 (issue MSV-9041), but the public record does not name chipsets or firmware versions. It is not on the CISA KEV list, has no known public proof of concept, and has no CVSS score yet.

What to do: Install the OEM or carrier firmware update that includes MediaTek modem patches MOLY01870473 and MOLY00814393 (issue MSV-9041). Until that update is available, treat unexpected cell connectivity as untrusted: the crash is reachable only after the device attaches to an attacker-controlled base station, and no fixed product version is named in the advisory.