CVE-2026-21551Network attack vector

Unauthenticated remote modem service interruption

Published Aug 3, 2026 · Updated Aug 3, 2026

Improper input validation in UNISOC T8100, T9100, T8200, and T8300 modems on Android 13 through 16 allows remote attackers to interrupt service. UNISOC has not disclosed the modem input path, message format, or validation operation that mishandles attacker-controlled data. No authentication or user interaction is required, and the published impact is limited to denial of service in the modem.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in UNISOC T8100, T9100, T8200, and T8300 modems on Android 13 through 16 allows remote attackers to interrupt service. UNISOC has not disclosed the modem input path, message format, or validation operation that mishandles attacker-controlled data. No authentication or user interaction is required, and the published impact is limited to denial of service in the modem.

The record

CVE
CVE-2026-21551
Published
Aug 3, 2026
Updated
Aug 3, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1642
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5UNISOCCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1642Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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