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Critical· 10actively exploitedofficial fix available

CVE-2026-34909

A Path Traversal flaw in UniFi OS devices lets a network attacker read or modify files on the underlying system, potentially giving them a system account. The vulnerability can be exploited without authentication and is reachable over the network.

publishedMay 22, 2026
last modifiedJul 23, 2026
sourcesNVD · CISA-KEV
severity · cvss
10
critical · how bad it is
exploitation · epss
63%
99th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 22, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

UniFi OS devices such as Dream Machine, Cloud Gateway, Dream Wall, and related firmware for enterprise and industrial gateways. Network administrators and IT staff managing these devices are the typical users.

02

Real-world impact

An attacker could read sensitive configuration files, alter system files, or gain a privileged account, leading to full control over the device and potentially the network it serves.

03

Why this severity

The CVSS score of 10 reflects that the flaw is network‑exposed, requires no authentication, and allows complete compromise of confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Follow the vendor’s instructions to mitigate the vulnerability.

CISA KEV required action

05

Timeline

  1. May 22, 2026 · May 22, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jun 23, 2026 · Jun 23, 2026
    Confirmed exploited (CISA KEV)
    CISA added it to the Known Exploited Vulnerabilities catalog — attackers are using it in the wild.
  3. Jun 26, 2026 · Jun 26, 2026
    CISA remediation deadline
    Federal agencies are required to remediate by this date.
  4. Jul 23, 2026 · 12d ago
    Advisory updated
    The NVD record was last revised.
  5. Jul 23, 2026 · 12d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeChanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →