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UniFi Access EUVDEUVD-2026-41384

| CVE-2026-50748 CRITICAL
Improper Input Validation (CWE-20)
2026-07-02 hackerone GHSA-fp2c-q39c-97j4
9.9
CVSS 3.1 · Vendor: hackerone
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach UniFi Access over network with low-priv account
  2. Delivery
    Submit input with shell metacharacters
  3. Exploit
    Bypass improper input validation
  4. Execution
    Inject command into host shell
  5. Persist
    Execute arbitrary code on host device
  6. Impact
    Compromise host beyond application scope

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions

Exploitation requires network access to the UniFi Access Application and a valid low-privilege account (CVSS PR:L) - this is authenticated exploitation, not unauthenticated. No user interaction is needed (UI:N) and complexity is low (AC:L). The specific enabling condition per the description is that attacker-controlled input reaches a command-execution path on the host due to improper input validation; the concrete injectable parameter/feature is not named in the available data. Limiting factors that reduce real-world exposure: an attacker must first obtain low-privilege credentials/access to the application, and must be able to reach it on the network, so instances isolated to trusted management networks are substantially harder to exploit.

Impact

The signals point to a genuine high priority. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H = 9.9) describes network-reachable, low-complexity exploitation needing only low privileges and no user interaction, with full confidentiality/integrity/availability impact and a scope break onto the host - effectively remote code execution for an authenticated user. Under an SSVC lens this trends toward high (network automatable exploitation, total technical impact), tempered by the PR:L authentication requirement, which raises the bar versus a fully unauthenticated flaw. Mitigating the urgency: no EPSS score was provided, the CVE is not in CISA KEV, and no public POC is referenced, so there is no evidence of active or widespread exploitation yet. The most notable data gap is the absence of an exact fixed version in the provided input - the reference is a vendor advisory bulletin rather than a pinned release - so defenders should confirm the patched build directly from Ubiquiti.

Exploit ScenarioDerived

An attacker who holds a low-privileged account on the UniFi Access Application and can reach it over the network submits crafted input to a field that is improperly validated, embedding shell metacharacters that the application passes to the host command interpreter. The injected commands execute on the underlying UniFi host device, giving the attacker code execution outside the application boundary. No public POC is referenced, and the low attack complexity (AC:L) means a working technique would be reliably repeatable once discovered.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.8% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 02, 2026

Command injection in Ubiquiti's UniFi Access Application lets a low-privileged attacker with network reach run arbitrary OS commands on the underlying host device, escaping the application into the operating system (CVSS 9.9, scope-changed). Improper input validation (CWE-20) means attacker-supplied data reaches a shell context; there is no public exploit identified at time of analysis, and the flaw is not listed in CISA KEV. Reported through HackerOne and addressed in Ubiquiti Security Advisory Bulletin 066.

RemediationAI

Patch available per vendor advisory - upgrade the UniFi Access Application to the fixed release described in Ubiquiti Security Advisory Bulletin 066 (https://community.ui.com/releases/Security-Advisory-Bulletin-066-066/984eceb3-49c8-4227-942d-671c289b3afc); the exact fixed version is not stated in the available data, so confirm the target build in that bulletin before scheduling the upgrade. Because exploitation requires network reachability plus low-privileged access, compensating controls until patched include restricting network access to the UniFi Access management interface and host to trusted administrative VLANs or management networks (limiting who can reach the low-privilege surface), tightening and auditing application account credentials to reduce the pool of low-privilege actors, and monitoring the host for anomalous process/command execution. These controls reduce reachability but do not remove the underlying injection, so patching remains the only complete fix.

Affected VersionsENISA

UniFi Access Application 0 <4.2.29

Affected Packages

euvd unifi_access_application fix: 4.2.29

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

UniFi Access is Ubiquiti's cloud-managed physical access-control platform (door readers, hubs, and the management application) that runs on UniFi host hardware such as UniFi OS Consoles/gateways. The root cause is CWE-20 Improper Input Validation: application input that should be treated as data is instead passed into a command/shell execution path on the host, yielding OS command injection. Because the injected command executes in the host operating system rather than inside the application sandbox, the CVSS scope is Changed (S:C) - the vulnerable component (the Access application) is used to compromise a different security authority (the host device). The affected component is identified in CPE as cpe:2.3:a:ubiquiti_inc:unifi_access_application, indicating the application layer of the product is the vulnerable surface.

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Severity by source

Vendor (hackerone) PRIMARY 9.9 CRITICAL
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI 9.9 CRITICAL

Network-reachable authenticated low-priv user (PR:L) triggers low-complexity command injection escaping the app to the host (S:C), yielding full C/I/A host compromise.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (hackerone).

CVSS VectorVendor: hackerone

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

1
Patch available
Jul 02, 2026 - 16:17 EUVD

DescriptionCVE.org

A malicious actor with access to the network and low privileges could exploit an Improper Input Validation vulnerability found in UniFi Access Application to execute a Command Injection on the host device.

Executive ViewAI

Why It Matters

Ubiquiti UniFi Access Application contains a critical command injection vulnerability (CVSS 9.9) that allows low-privileged attackers to execute arbitrary operating system commands and escape the application container. Organizations relying on UniFi Access for physical or logical access control face immediate risk of complete infrastructure compromise, potentially enabling unauthorized access to secured facilities and business-critical systems.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Recommended interim mitigations: implement strict network segmentation isolating UniFi Access systems; enforce principle of least privilege for administrative access; deploy network-based intrusion detection and logging for the application; disable non-essential features until patched; monitor system logs and command execution for exploitation attempts.

Threat Intelligence Overview

EPSS Score
0.8%
Top 48% exploitable
Prevalence
Medium
Ubiquiti is widely deployed, but Access is a specific door-control add-on product
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.8%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Very High
Technical Impact
Total

Priority Score

51
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +50
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

OS command injection occurs when an application passes unsanitized user input directly into system shell commands.

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