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

Source: https://junglewise.ai/threats/cve-2026-20566-in-modem-there-is-a-possible-out-of-bounds-write-due-to-a-missing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-02. Updated: 2026-11-02  
License: CC BY 4.0 with a link back

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](https://junglewise.ai/threats/technologies/modem). Vendors: [MediaTek](https://junglewise.ai/threats/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

- [https://www.mediatek.com/product-security-bulletin/November-2026](https://www.mediatek.com/product-security-bulletin/November-2026)

## Related threats

- [MediaTek Modem privilege escalation via permissions bypass](https://junglewise.ai/threats/cve-2026-68591-in-modem-there-is-a-possible-escalation-of-privilege-due-to-a)
- [MediaTek Modem out-of-bounds write privilege escalation](https://junglewise.ai/threats/cve-2026-68589-in-modem-there-is-a-possible-out-of-bounds-write-due-to-a-missing)
- [MediaTek Modem integer overflow denial of service](https://junglewise.ai/threats/cve-2026-68588-in-modem-there-is-a-possible-way-for-xxx-to-xxxxx-due-to-an)
- [MediaTek Modem logic error denial of service](https://junglewise.ai/threats/cve-2026-20600-in-modem-there-is-a-possible-application-crash-due-to-a-logic)
- [MediaTek Modem privilege escalation due to missing permission check](https://junglewise.ai/threats/cve-2026-20599-in-modem-there-is-a-possible-escalation-of-privilege-due-to-a)