CVE-2026-21638

Adjacent code execution via airMAX command injection

Published Jan 8, 2026 · Updated Jan 8, 2026

Command injection in Ubiquiti UBB before 3.1.7 and UBB-XG before 1.2.3 allows attackers in Wi-Fi range to execute code. Ubiquiti identifies the airMAX Wireless Protocol as the vulnerable locus but has not disclosed which protocol field reaches a command interpreter or how special elements escape neutralization. The attack requires no privileges or user interaction but requires adjacent Wi-Fi proximity; successful exploitation grants code execution on the bridge with confidentiality, integrity, and availability impact.

CVSS severity8.8
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Ubiquiti UBB before 3.1.7 and UBB-XG before 1.2.3 allows attackers in Wi-Fi range to execute code. Ubiquiti identifies the airMAX Wireless Protocol as the vulnerable locus but has not disclosed which protocol field reaches a command interpreter or how special elements escape neutralization. The attack requires no privileges or user interaction but requires adjacent Wi-Fi proximity; successful exploitation grants code execution on the bridge with confidentiality, integrity, and availability impact.

The record

CVE
CVE-2026-21638
Published
Jan 8, 2026
Updated
Jan 8, 2026
Vendor
Ubiquiti Inc.
Product
Building Bridge
Classifications
CWE-77, T1059
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.1.7

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Ubiquiti Inc. · Building Bridgeversion=0 <3.1.7
Ubiquiti Inc. · Building Bridge XGversion=0 <1.2.3

Published CVSS scores

8.8HackerOneCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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