Is CVE-2026-21638 in the CISA KEV catalog?

No. CVE-2026-21638 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-21638?

CVE-2026-21638 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2026-21638?

CVE-2026-21638 has an EPSS score of 0.38% (30th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-21638

HIGH

8.8

CVSS v3

NVD

Description

A malicious actor in Wi-Fi range of the affected product could leverage a vulnerability in the airMAX Wireless Protocol to achieve a remote code execution (RCE) within the affected product. Affected Products: UBB-XG (Version 1.2.2 and earlier) UDB-Pro/UDB-Pro-Sector (Version 1.4.1 and earlier) UBB (Version 3.1.5 and earlier) Mitigation: Update your UBB-XG to Version 1.2.3 or later. Update your UDB-Pro/UDB-Pro-Sector to Version 1.4.2 or later. Update your UBB to Version 3.1.7 or later.

CWE-77Command Injection

CVSS v3 Vector

Exploitability

Attack VectorAdjacent

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.38%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

https://community.ui.com/releases/Security-Advisory-Bulletin-060-060/cde18da7-2bc4-41bb-a9cc-48a4a4c479c1

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-01-14.