---
id: CVE-2026-20557
title: >-
  In Modem, there is a possible out of bounds write due to a missing bounds
  check
summary: >-
  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 pr…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: adp
cwe:
  - CWE-787
vendor: 'MediaTek, Inc.'
product: MediaTek chipset
affected:
  - mediatek_chipset MT2716
  - mediatek_chipset MT6813
  - mediatek_chipset MT6815
  - mediatek_chipset MT6835
  - mediatek_chipset MT6858
  - mediatek_chipset MT6878
  - mediatek_chipset MT6881
  - mediatek_chipset MT6897
  - mediatek_chipset MT6899
  - mediatek_chipset MT6982
  - mediatek_chipset MT6986
  - mediatek_chipset MT6988
  - mediatek_chipset MT6991
  - mediatek_chipset MT6993
  - mediatek_chipset MT8668
  - mediatek_chipset MT8676
  - mediatek_chipset MT8678
  - mediatek_chipset MT8755
  - mediatek_chipset MT8775
  - mediatek_chipset MT8792
  - mediatek_chipset MT8793
  - mediatek_chipset MT8863
  - mediatek_chipset MT8873
  - mediatek_chipset MT8875
  - mediatek_chipset MT8883
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-02T00:00:00+00:00'
published: '2026-11-02'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T04:55:35.117Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-20557'
references:
  - url: 'https://www.mediatek.com/product-security-bulletin/November-2026'
tags:
  - cve.org
epss: 0.00232
epssPercentile: 0.14221
ingestedAt: '2026-11-05T20:33:06.667Z'
---

## Overview

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: MOLY01877236; Issue ID: MSV-9804.

## Affected

- `mediatek_chipset MT2716`
- `mediatek_chipset MT6813`
- `mediatek_chipset MT6815`
- `mediatek_chipset MT6835`
- `mediatek_chipset MT6858`
- `mediatek_chipset MT6878`
- `mediatek_chipset MT6881`
- `mediatek_chipset MT6897`
- `mediatek_chipset MT6899`
- `mediatek_chipset MT6982`
- `mediatek_chipset MT6986`
- `mediatek_chipset MT6988`
- `mediatek_chipset MT6991`
- `mediatek_chipset MT6993`
- `mediatek_chipset MT8668`
- `mediatek_chipset MT8676`
- `mediatek_chipset MT8678`
- `mediatek_chipset MT8755`
- `mediatek_chipset MT8775`
- `mediatek_chipset MT8792`
- `mediatek_chipset MT8793`
- `mediatek_chipset MT8863`
- `mediatek_chipset MT8873`
- `mediatek_chipset MT8875`
- `mediatek_chipset MT8883`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.