How severe is CVE-2026-54403?

CVE-2026-54403 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-54403 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-54403?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-54403 published?

CVE-2026-54403 was published on 2026-07-02.

CVE-2026-54403

CVE-2026-54403 is a high-severity vulnerability with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: High (CVSS 3.x base score 8.6)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Published: 2026-07-02
Last modified: 2026-07-02

Description

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.

Frequently asked questions

What is 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 devices or instances.
How severe is CVE-2026-54403?: CVE-2026-54403 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-54403 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-54403?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-54403 published?: CVE-2026-54403 was published on 2026-07-02.

References

https://community.ui.com/releases/Security-Advisory-Bulletin-066-066/984eceb3-49c8-4227-942d-671c289b3afc

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