---
id: CVE-2026-66086
title: >-
  In the modem OTA stack, there is a possible stack-based buffer overflow due to
  improper validation of scheduling information in SIB1 messages
summary: >-
  In the modem OTA stack, there is a possible stack-based buffer overflow due to
  improper validation of scheduling information in SIB1 messages. This could
  lead to remote code execution or denial of service with no additional
  execution pri…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-121
vendor: 'Unisoc (Shanghai) Technologies Co., Ltd.'
product: Modem
affected:
  - Modem T8100
  - Modem T9100
  - Modem UDX710
published: '2026-10-12'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:55:59.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-66086'
references:
  - url: >-
      https://www.unisoc.com/en/support/product-security-bulletin/2109454821805424641
    label: security@unisoc.com
tags:
  - nvd
  - cve.org
epss: 0.00455
epssPercentile: 0.39345
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-15T18:01:14.326188Z'
scores:
  nvd: 9.8
  cna: 8.3
ingestedAt: '2026-10-12T14:50:34.075Z'
---

## Overview

In the modem OTA stack, there is a possible stack-based buffer overflow due to improper validation of scheduling information in SIB1 messages. This could lead to remote code execution or denial of service with no additional execution privileges needed.

## Remediation

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