How severe is CVE-2026-21638?

CVE-2026-21638 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-21638 being actively exploited?

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

What products are affected by CVE-2026-21638?

CVE-2026-21638 primarily affects Ui Ubb-xg Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-21638?

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.

Does CVE-2026-21638 have an EU (EUVD) identifier?

Yes. CVE-2026-21638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1491.

When was CVE-2026-21638 published?

CVE-2026-21638 was published on 2026-01-08 and last updated on 2026-06-17.

CVE-2026-21638

CVE-2026-21638 is a high-severity vulnerability in Ui Ubb-xg Firmware with a CVSS 3.x base score of 8.8. 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-77.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-1491
Weakness: CWE-77
Affected product: Ui Ubb-xg Firmware
Published: 2026-01-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-21638?: 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.
How severe is CVE-2026-21638?: CVE-2026-21638 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-21638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21638?: CVE-2026-21638 primarily affects Ui Ubb-xg Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-21638?: 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.
Does CVE-2026-21638 have an EU (EUVD) identifier?: Yes. CVE-2026-21638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1491.
When was CVE-2026-21638 published?: CVE-2026-21638 was published on 2026-01-08 and last updated on 2026-06-17.

References

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

Affected products (4)

cpe:2.3:o:ui:ubb-xg_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:ui:udb-pro_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:ui:udb-pro-sector_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:ui:ubb_firmware:*:*:*:*:*:*:*:*

Other CWE-77 (Command Injection) vulnerabilities

CVE-2026-23652 — Critical (CVSS 10.0): Improper neutralization of special elements used in a command ('command injection') in Microsoft Power Pages allows an…
CVE-2025-59818 — Critical (CVSS 10.0): This vulnerability allows authenticated attackers to execute arbitrary commands on the underlying system using the file…
CVE-2025-64093 — Critical (CVSS 10.0): Remote Code Execution vulnerability that allows unauthenticated attackers to inject arbitrary commands into the…
CVE-2025-64090 — Critical (CVSS 10.0): This vulnerability allows authenticated attackers to execute commands via the hostname of the device.
CVE-2025-61492 — Critical (CVSS 10.0): A command injection vulnerability in the execute_command function of terminal-controller-mcp 0.1.7 allows attackers to…
CVE-2025-10035 — Critical (CVSS 10.0): A deserialization vulnerability in the License Servlet of Fortra's GoAnywhere MFT allows an actor with a validly forged…

Browse all CWE-77 (Command Injection) vulnerabilities →