How severe is CVE-2026-55110?

CVE-2026-55110 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-55110 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-55110?

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-2026-55110 published?

CVE-2026-55110 was published on 2026-07-02.

CVE-2026-55110

CVE-2026-55110 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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-942.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-942
Published: 2026-07-02
Last modified: 2026-07-02

Description

A malicious actor who lures an authenticated user to a malicious page could exploit a Cross-Origin Resource Sharing (CORS) misconfiguration found in UniFi OS to trigger actions in UniFi OS using that user's session.

Frequently asked questions

What is CVE-2026-55110?: A malicious actor who lures an authenticated user to a malicious page could exploit a Cross-Origin Resource Sharing (CORS) misconfiguration found in UniFi OS to trigger actions in UniFi OS using that user's session.
How severe is CVE-2026-55110?: CVE-2026-55110 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-55110 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-55110?: 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-2026-55110 published?: CVE-2026-55110 was published on 2026-07-02.

References

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

Other CWE-942 vulnerabilities

CVE-2022-26969 — Critical (CVSS 9.8): In Directus before 9.7.0, the default settings of CORS_ORIGIN and CORS_ENABLED are true.
CVE-2022-31736 — Critical (CVSS 9.8): A malicious website could have learned the size of a cross-origin resource that supported Range requests. This…
CVE-2026-34449 — Critical (CVSS 9.6): SiYuan is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code…
CVE-2026-30924 — Critical (CVSS 9.6): qui is a web interface for managing qBittorrent instances. Versions 1.14.1 and below use a permissive CORS policy that…
CVE-2026-9739 — Critical (CVSS 9.4): Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented…
CVE-2026-8948 — Critical (CVSS 9.1): Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird…

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