# CVE-2026-20562: MediaTek Modem out of bounds write due to missing bounds check

Source: https://junglewise.ai/threats/cve-2026-20562-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-2026-20562 · Severity: info · Published 2026-11-02

MediaTek modem firmware used in 5G and 4G devices contains an out of bounds write vulnerability caused by a missing bounds check. An attacker controlling a rogue cellular base station can remotely exploit this vulnerability to cause a denial of service (device crash or malfunction) without requiring any special privileges or user interaction.

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

## Quick answers

**Is CVE-2026-20562 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20562 being exploited in the wild.

**How severe is CVE-2026-20562?** Informational severity, published 2 November 2026.

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

**Is there a fix for CVE-2026-20562?** 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-2026-20562 attacked?** It is attacked over the network, in device firmware.

**Am I affected by CVE-2026-20562?** 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 exists in MediaTek modem firmware due to insufficient bounds validation. The vulnerability can be triggered remotely when a user equipment (UE) connects to an attacker-controlled base station, requiring only network-level access and no prior authentication. Successful exploitation results in denial of service of the modem component.

## Affected products

- MediaTek Modem

## Timeline

- 2026-11-02: advisory

## 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)