What is CVE-2026-34909?
A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to access an underlying account.
The record classifies CVE-2026-34909 under weakness class CWE-22. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 10 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 159 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 10 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 1.7% probability of exploitation in the next 30 days, higher than 77.7% of all scored CVEs
- CISA KEV
- Listed since 2026-06-23, federal remediation deadline 2026-06-26
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-05-22, last modified 2026-06-24
Is CVE-2026-34909 being exploited?
CISA added CVE-2026-34909 to the Known Exploited Vulnerabilities catalog on 2026-06-23, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-06-26 under BOD 22-01. Weaponised exploit code for CVE-2026-34909 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 42 in the Threadlinqs vulnerability feed.
- trickest/cve (trickest)
Affected products and versions
- Ubiquiti Inc: UniFi OS Server, Express, UDM, UDM-Pro, UDM-SE, UDM-Pro-Max, UDM-Beast, EFG, UDW, UDR
How to fix CVE-2026-34909
Because CVE-2026-34909 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-06-26. No vendor patch reference has been recorded for CVE-2026-34909 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-34909
5 tracked threats in the Threadlinqs corpus reference CVE-2026-34909, either in the campaign’s CVE list or as an indicator on the campaign record.
- Chinese-Speaking 'Kapibala' Actor (Red Heron-Linked) Chains WordPress wp2shell, Zyxel GS1900, and Ubiquiti UniFi OS Flaws to Steal Government Data — CRITICAL · 2026-09-22
- CVE-2026-50746: Critical Unauthenticated Command Injection in Ubiquiti UniFi Connect Application (CVSS 10.0) — CRITICAL · 2026-07-10
- CISA BOD 26-04: Risk-Based Vulnerability Remediation and CISO Reporting Mandate for FCEB Agencies — MEDIUM · 2026-07-06
- UniFi OS Server Pre-Auth RCE Chain (CVE-2026-34908/34909/34910): x-original-uri Auth-Gateway Bypass + package-update Command Injection — CRITICAL · 2026-06-08
- Ubiquiti UniFi OS — Three Max-Severity Pre-Auth Vulnerabilities (CVE-2026-34908 / 34909 / 34910) in Security Advisory Bulletin 064 — CRITICAL · 2026-05-22
Sources
Enriched from CVE.org, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on .