In 2026, a critical vulnerability surfaced affecting public dashboards across several analytics platforms — logged as CVE-2026-21722. In essence, anyone accessing a dashboard with annotations could read annotation history outside the dashboard’s restricted (“locked”) timerange. This bug didn’t reveal private data, but gave unintended access to annotation histories that should have been out of bounds.

Let’s break this down, examine original sources, analyze with example code, and see how a potential attacker could have used this bug — all in plain language.

Vulnerability Overview

When teams share analytics dashboards with the public — whether financial metrics, product uptime, or any other data — they often restrict the time seen. For instance, you might lock the timerange to “last week only.” But every good chart is annotated with incident notes, release dates, or other points of interest.

The flaw: If a user opened the dashboard and used the annotation feature, they could freely change the annotation's time window — bypassing the locked dashboard time setting. This revealed the full history of every annotation tied to the dashboard, not just those within the current range.

Example scenario:
Let’s say Annotation A is at 2022-01-01, and Annotation B is at 2023-01-01. The dashboard is locked to display data from 2023 only. If you tweak the timerange within the annotation tool, you can still view Annotation A.

- The problem: Restriction boundaries were ignored, letting people see annotation context from any period, even if the data itself was blocked.

Suppose a dashboard is rendered with something like this JavaScript snippet

// Hypothetical dashboard setup
const DASHBOARD_LOCKED_RANGE = {
  from: "2023-01-01",
  to: "2023-12-31"
};

function getAnnotations(range) {
  // Makes API call to backend
  fetch(/api/annotations?from=${range.from}&to=${range.to})
    .then(r => r.json())
    .then(showAnnotations);
}

// User should only see:
getAnnotations(DASHBOARD_LOCKED_RANGE);

But in the vulnerable version, the annotation UI let users set their own timerange

// This range comes from the annotation panel inputs, not enforced by dash config
const userSelectedRange = getUserInputRange();

getAnnotations(userSelectedRange); // Potentially outside of locked range!

Here’s how the actual HTTP request could look (for Grafana and similar platforms)

GET /api/annotations?from=201-01-01T00:00:00Z&to=203-01-01T00:00:00Z
Authorization: Bearer <public_token>

- The API didn’t verify whether the from and to values were inside the dashboard's locked timeframe.

Visit the public dashboard.

2. Open the annotation tool or directly fiddle with annotation API calls using tools like curl or browser dev tools.

Python Exploit Example

Here’s a simple Python snippet showing how someone might fetch all annotations, given a public dashboard token:

import requests

url = 'https://analytics.example.com/api/annotations';
params = {
    'from': '200-01-01T00:00:00Z',
    'to':   '210-01-01T00:00:00Z'
}
headers = {'Authorization': 'Bearer PUBLIC_DASHBOARD_TOKEN'}

resp = requests.get(url, params=params, headers=headers)
if resp.ok:
    for anno in resp.json():
        print(anno)

What Was Exposed

- Anyone could see all annotation notes made to a public dashboard, regardless of the intended time lock.

No private or hidden annotations (not meant for public) were leaked.

- But notes revealing sensitive operational info, incident history, or release timelines might be revealed unintentionally.

Official Response

Platforms affected by CVE-2026-21722 (see Grafana’s security advisory, for instance) patched this by:

- Enforcing backend checks: The annotation API now only allows requests within the dashboard’s lock range for public shares.

References

- CVE-2026-21722 at MITRE
- Grafana Security Advisory (2026-06)
- Public Dashboard Annotations and Timerange Issues - GitHub Report

Conclusion

CVE-2026-21722 is a lesson in not trusting frontend limits: backend endpoints must always re-check permission boundaries. This flaw didn’t leak data that wasn’t supposed to be public, but it did open a window into historical notes admins probably didn’t expect to show. Always keep annotation APIs and frontend controls in sync — and keep your analytics platforms updated!

*For sysadmins and dashboard builders: Audit your sharing features, and make sure the access controls are enforced server-side, not just in the browser.*

Timeline

Published on: 02/12/2026 08:49:05 UTC
Last modified on: 02/12/2026 15:10:37 UTC