# CVE-2026-20551: MediaTek GNSS out of bounds write due to missing bounds check

Source: https://junglewise.ai/threats/cve-2026-20551-in-gnss-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-2026-20551 · Severity: info · Published 2026-11-02

A missing bounds check in MediaTek's GNSS (Global Navigation Satellite System) component can allow a local attacker to write data outside allocated memory boundaries. This vulnerability can cause the system to crash or become unresponsive, resulting in denial of service. User interaction is required for exploitation, but no special privileges are needed.

Technologies: [MediaTek Dimensity 5G](https://junglewise.ai/threats/technologies/dimensity-5g), [MediaTek Helio 4G](https://junglewise.ai/threats/technologies/helio-4g). Vendors: [MediaTek](https://junglewise.ai/threats/vendors/mediatek).

## Quick answers

**Is CVE-2026-20551 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20551 being exploited in the wild.

**How severe is CVE-2026-20551?** Informational severity, published 2 November 2026.

**Which products and versions are affected?** MediaTek Dimensity 5G; MediaTek Helio 4G.

**Is there a fix for CVE-2026-20551?** 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-2026-20551 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2026-20551?** Check whether you run MediaTek Dimensity 5G or MediaTek Helio 4G. 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 the GNSS subsystem due to insufficient bounds validation, allowing an attacker with local access and user interaction to write beyond allocated buffer boundaries. The vulnerability impacts memory integrity and can be exploited to crash the system or trigger unexpected behavior. While the advisory indicates the issue affects multiple MediaTek chipsets, specific patch availability and affected versions are referenced by Patch ID ALPS11309305 and Issue ID MSV-10730.

## Affected products

- MediaTek Dimensity 5G
- MediaTek Helio 4G

## Timeline

- 2026-11-02: disclosed

## References

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

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