Cyber Resilience

CVE-2026-34910

Ui Unifi Os Server ≤ 5.0.8

CISA KEVActive ExploitationPublic PoC
Published
22 May 2026
Modified
23 July 2026
KEV Added
23 June 2026
Patch / advisory
CVSS Score v3.1 10.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.87 99.7th percentile
Risk Priority 100 floored blend · peak EPSS

Summary

CVE-2026-34910 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Ui Unifi Os Server. Its CVSS base score is 10.0 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A malicious actor with network access could exploit an Improper Input Validation vulnerability (CWE-20) in UniFi OS devices to perform command injection. The flaw carries a CVSS 3.1 base score of 10.0, reflecting network attack vector, low complexity, no required privileges or user interaction, and changed scope with high impact on confidentiality, integrity, and availability.

An unauthenticated attacker reachable over the network can supply crafted input that results in arbitrary command execution on the affected device, potentially allowing full compromise of the UniFi OS system and any connected infrastructure.

Ubiquiti has published Security Advisory Bulletin 064, available at the referenced community.ui.com URL, which addresses the issue for UniFi OS devices. The EPSS score remains flat at 0.1815 with no material increase observed since disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection.

CWE(s)
KEV Date Added
23 June 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1036.001 Invalid Code Signature Stealth
Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-34909Same product: Ui Enterprise Fortress Gatewayboth on KEV
CVE-2026-34908Same product: Ui Enterprise Fortress Gatewayboth on KEV
CVE-2026-54402Same product: Ui Enterprise Fortress Gateway
CVE-2026-34911Same product: Ui Enterprise Fortress Gateway
CVE-2026-54403Same product: Ui Enterprise Fortress Gateway
CVE-2026-54401Same product: Ui Enterprise Fortress Gateway
CVE-2026-54404Same product: Ui Enterprise Fortress Gateway
CVE-2026-33000Same product: Ui Unifi Os Server
CVE-2026-50748Same vendor: Ui
CVE-2026-54405Same vendor: Ui

Affected Assets

ui
unifi os server
≤ 5.0.8
ui
unifi cloud gateway industrial firmware
≤ 5.1.12
ui
unifi dream machine firmware
≤ 5.1.12
ui
unifi dream machine pro firmware
≤ 5.1.12
ui
unifi dream machine special edition firmware
≤ 5.1.12
ui
unifi dream machine pro max firmware
≤ 5.1.12
ui
enterprise fortress gateway firmware
≤ 5.1.12
ui
unifi dream wall firmware
≤ 5.1.12
ui
unifi dream router firmware
≤ 5.1.12
ui
unifi dream router 7 firmware
≤ 5.1.12
+21 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing input validation through analysis or test cases.

SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.

Requiring documented development standards and tools can embed input-validation practices into the engineering process.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

prevents

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

none

Regular automated validation of system software and data content, combined with scanning of all inbound files, enforces input validation at the boundary before untrusted content is processed.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References