What is CVE-2026-121816?

CVE-2026-121816 is a high-severity vulnerability in About Time Technologies Herowatch Mini, classified under Missing Authentication for Critical Function. CVSS score: 8.8/10. Published 2026-11-04.

How severe is CVE-2026-121816?

High severity. CVSS v3 base score is 8.8 out of 10.

Auth bypass in About Time Technologies Herowatch Mini

CVE-2026-121816

Herowatch Mini developed by About Time Technologies has a Missing Authentication vulnerability. Unauthenticated remote attackers can connect to the affected device's ADB service and obtain an ADB shell, thereby accessing device resources or performing related operations.

Vulnerability class: Broken Authentication

Published 2026-11-04.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

About Time Technologies Herowatch Mini

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

www.twcert.org.tw/tw/cp-132-11355-341da-1.html (third-party-advisory)
www.twcert.org.tw/en/cp-139-11356-8292a-2.html (third-party-advisory)

Frequently asked questions

What is CVE-2026-121816?: CVE-2026-121816 is a high-severity vulnerability in About Time Technologies Herowatch Mini, classified under Missing Authentication for Critical Function. CVSS score: 8.8/10. Published 2026-11-04.
How severe is CVE-2026-121816?: High severity. CVSS v3 base score is 8.8 out of 10.