# CVE-2026-20549: MediaTek Modem out of bounds write in input validation

Source: https://junglewise.ai/threats/cve-2026-20549-in-modem-there-is-a-possible-out-of-bounds-write-due-to-improper  
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-2026-20549 · Severity: info · Published 2026-11-02

MediaTek modems are cellular chipsets used in smartphones and IoT devices to connect to mobile networks. An attacker controlling a rogue base station can exploit improper input validation to write data outside intended memory boundaries, gaining the ability to execute arbitrary code and take complete control of the device. No user interaction or special privileges are required for exploitation.

Technologies: [MediaTek Modem](https://junglewise.ai/threats/technologies/modem). Vendors: [MediaTek](https://junglewise.ai/threats/vendors/mediatek).

## Quick answers

**Is CVE-2026-20549 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20549 being exploited in the wild.

**How severe is CVE-2026-20549?** Informational severity, published 2 November 2026.

**Which products and versions are affected?** MediaTek Modem.

**Is there a fix for CVE-2026-20549?** 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-2026-20549 attacked?** It is attacked over the network or from the adjacent network.

**Am I affected by CVE-2026-20549?** 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 vulnerability in MediaTek modem firmware results from insufficient input validation when processing network traffic. The vulnerability can be triggered remotely by a device connected to an attacker-controlled base station, leading to privilege escalation and potentially arbitrary code execution. The attack requires network-adjacent access via a rogue base station but no authentication or special UE privileges.

## 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)