CVE-2026-54403: A malicious actor with access to the network could exploit a Path Traversal vulnerability found in certain devices running UniFi OS to bypass authentication of such UniFi OS device

highCVSS 8.6CVE-2026-54403

A malicious actor with access to the network could exploit a Path Traversal vulnerability found in certain devices running UniFi OS to bypass authentication of such UniFi OS devices or instances.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 8.6
Published: 2026-07-02
Last updated: 2026-07-02
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-54403

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-544030.46% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 37% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-54403	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownNCSC-2026-0221 [1.00] [M/H] Vulnerabilities fixed in UniFi products from Ubiquiti Networksncsc-nl
high[UPDATE] [high] Ubiquiti UniFi: Multiple vulnerabilitiescert-bund

Recent advisories for A malicious actor

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-56842: A malicious actor with access to the network and under certain conditions could exploit an Inc…nvd · 2026-07-02
highCVE-2026-56841: A malicious actor with access to the network and low privileges could exploit an authenticated…nvd · 2026-07-02
highCVE-2026-55119: A malicious actor with access to the network and low privileges could exploit an Improper Acce…nvd · 2026-07-02
highCVE-2026-55118: A malicious actor with access to the network,low privileges and under certain conditions could…nvd · 2026-07-02
highCVE-2026-55117: A malicious actor with access to the network could exploit a Path Traversal vulnerability foun…nvd · 2026-07-02
criticalCVE-2026-55116: A malicious actor with access to the network and under certain network configurations could ex…nvd · 2026-07-02