CVE-2026-20555: MediaTek Modem out of bounds read due to missing bounds check

CVE-2026-20555 · Severity: info · Published 2026-11-02

A vulnerability in MediaTek modem firmware allows an attacker to trigger a remote denial of service by exploiting an out-of-bounds memory read. An attacker controlling a rogue cellular base station can crash the modem without needing special privileges or user interaction, causing the device to lose connectivity or become unresponsive.

Technologies: MediaTek Modem. Vendors: MediaTek.

Quick answers

Is CVE-2026-20555 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-20555 being exploited in the wild.
How severe is CVE-2026-20555?
Informational severity, published 2 November 2026.
Which products and versions are affected?
MediaTek Modem.
Is there a fix for CVE-2026-20555?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-20555 attacked?
It is attacked over the network or from the adjacent network, in device firmware.
Am I affected by CVE-2026-20555?
Check whether you run MediaTek Modem. 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

An out-of-bounds read in the modem firmware results from a missing bounds check during base station communication processing. The vulnerability is triggered when a user equipment connects to an attacker-controlled rogue base station, exploitable over the network without prior authentication. Successful exploitation causes a denial of service condition in the modem.

Affected products

  • MediaTek Modem

Timeline

  • 2026-11-02: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.