---
id: "CVE-2026-121817"
kind: "vulnerability"
aliases: ["CVE-2026-121817"]
title: "Herowatch Go Server: insecure object reference exposes other users' data"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Herowatch Go Server", "fixed": [], "affected": "all versions", "ecosystem": "vendor"}]
ecosystems: []
tags: ["end-of-life", "herowatch", "herowatch-go-server", "idor", "other", "self-hosted"]
not_affected_if: ["unknown"]
published_at: "2026-11-04T07:17:12+00:00"
first_seen_at: "2026-11-04T07:25:30+00:00"
updated_at: "2026-11-04T07:27:31+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121817", "first_seen_at": "2026-11-04T07:25:30+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-11-04T07:27:31+00:00"}]
---

# Herowatch Go Server: insecure object reference exposes other users' data

Herowatch Go Server from About Time Technologies has an insecure direct object reference flaw. A logged-in user can change request parameters to read or act on other users' data and functions.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Herowatch Go Server affected all versions fixed ?

## How to check

Check whether you use the Herowatch Go app/server (About Time Technologies). All versions are listed as affected; the advisory gives no version check or endpoint list.

## Fix

No fix: TWCERT/CC says the product is no longer maintained; replace it with a supported device.

## Timeline

- 2026-11-04T07:25:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121817
- 2026-11-04T07:27:31+00:00 analyst — TWCERT/CC (CNA) advisory read: all versions affected, product no longer maintained, no fix. Endpoints/parameters not published. No exploitation or PoC found.

## Documents

- [advisory] TWCERT/CC TVN-202611002: Herowatch Go Server - Insecure Direct Object Reference https://www.twcert.org.tw/en/cp-139-11364-0dce6-2.html

## From the sources

Herowatch Go Server developed by About Time Technologies has a Insecure Direct Object Reference vulnerability. Authenticated remote attackers can modify specific parameters to access or operate other users' data and functions.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_