# CVE-2026-121818: About Time Technologies｜Herowatch Go - Security Misconfiguration

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

Herowatch Mini developed by About Time Technologies has a system signing vulnerability. Authenticated local attackers can exploit a publicly available test key to sign malicious programs, allowing them to elevate privileges and execute arbitrary code.

## Remediation

- fix: The product is no longer maintained. Users are advised to replace it with a supported device. (source: CNA: twcert)

## Affected products and versions

- About Time Technologies / Herowatch Go: all (affected, custom). Source: CNA: twcert

## Severity and prioritization

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: twcert

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: twcert

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-1394

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://www.twcert.org.tw/en/cp-139-11362-1e829-2.html (CNA: twcert; third-party-advisory)

- https://www.twcert.org.tw/tw/cp-132-11360-ab123-1.html (CNA: twcert; third-party-advisory)

## Provenance

- CNA: twcert: https://www.cve.org/CVERecord?id=CVE-2026-121818; retrieved 2026-11-04; source updated 2026-11-04

Revision: 97da4a1966eb89642bd7a752f790e1dae443d50aaadddd095beb088ba19c560f

Canonical: https://y2.dev/cve/CVE-2026-121818

## Agent and API access

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- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

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- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

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