CVE-2026-20566: MediaTek Modem out-of-bounds write in bounds check

CVE-2026-20566 · Severity: info · Published 2026-11-02

MediaTek modems are cellular radio components used in smartphones and connected devices. An out-of-bounds write vulnerability in the modem's packet processing can crash the device (denial of service) when connected to a malicious base station. Exploitation requires the attacker to first obtain system-level privileges and requires user interaction, limiting the practical risk.

Technologies: MediaTek Modem. Vendors: MediaTek.

Quick answers

Is CVE-2026-20566 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-20566 being exploited in the wild.
How severe is CVE-2026-20566?
Informational severity, published 2 November 2026.
Which products and versions are affected?
MediaTek Modem.
Is there a fix for CVE-2026-20566?
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-2026-20566 attacked?
It is attacked over the network or from the adjacent network, in device firmware.
Am I affected by CVE-2026-20566?
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 write due to missing bounds checking in MediaTek modem firmware allows memory corruption when processing specially crafted signals from a rogue base station. Exploitation requires system privilege access and user interaction; successful exploitation results in remote denial of service. MediaTek has issued patches identified by Patch ID MOLY01923663 / ALPS11315955.

Affected products

  • MediaTek Modem

Timeline

  • 2026-11-02: disclosed

References

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