December 2025
11
min read

Using Gemini 3? Here’s What You Should Never Share With It

Alefiyah Bhatia
Growth Marketing Specialist

Table of Contents

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The ultimate showdown between Gemini 3 and ChatGPT 5.2 is intensifying.

But in a bid for your data, which one of these titans win and what is the actual cost of accelerating adoption without proper guardrails?

While we’ve mapped out the ChatGPT data breaches timeline, It is just as important to examine the risks emerging on Google’s side. What is the cost of exposing sensitive data, compromising privacy, or allowing an AI system to observe every digital step you take?

GeminiJack - The vulnerability that changed how companies think about Gemini 3

The disclosure of GeminiJack in late 2025 forced security teams to reconsider how much trust they place in Gemini 3. Researchers showed that a malicious prompt could be hidden inside a normal Google Doc, email, or calendar invite. When an employee later interacted with Gemini, the model obeyed the hidden instruction and pulled internal data it was never meant to retrieve.

There was no phishing link, no malware, and no unusual user behavior. The issue stemmed from how Gemini interprets workspace content and how easily that interpretation can be manipulated once the model has broad access to company data.

It became clear that the risk is not limited to what employees type into Gemini. It includes everything Gemini can read, everything it connects to, and everything it is allowed to act on across the organization.

Gemini now sits inside mission-critical workflows

Gemini 3 is no longer an isolated chatbot. It is built into Gmail, Docs, Drive, Calendar, internal knowledge bases, shared folders, customer-facing teams, and analytical workflows. Employees rely on it to summarize transcripts, rewrite customer messages, analyze contracts, check financial logic, and search through organizational data.

This central position improves productivity, but it also means Gemini operates at the intersection of sensitive information and day-to-day decision-making. Each AI-assisted task becomes a potential point of exposure. Each document or email becomes a potential directive the model may follow. And every retrieval event is tied directly to systems that store regulated data, confidential plans, or proprietary knowledge.

This is why companies need a clear understanding of what should never be shared with Gemini 3, even during normal usage, and why automated redaction and controlled workflows are now becoming essential rather than optional.

Real-World Gemini Vulnerabilities Companies Need to Know

Beyond the GeminiJack disclosure already discussed, Google’s broader Gemini ecosystem has been the subject of multiple real security findings. These issues span prompt injection risks, developer tooling weaknesses, and platform-level vulnerabilities observed in production or pre-production environments. Together, they illustrate how an AI system integrated deeply into Workspace and cloud workflows can create new exposure points for organizations.

1. Google’s Acknowledged Prompt Injection Risks

Google’s documentation confirms that Gemini models can be affected by prompt injection, including indirect forms of it, where hidden instructions inside text cause the AI to behave unexpectedly. This does not require malicious code. A crafted phrase inside a document, email, or shared workspace file can shift how Gemini interprets a user’s request.

These attacks are significant because Workspace content often appears harmless, and the model may not reliably distinguish instructions from context, especially when operating across long-context prompts or automated workflows.

Source: Google Workspace Security Guidance

2. Historical Multi-Vector Weaknesses Identified by Tenable Research

Tenable researchers previously identified three vulnerabilities affecting components of the Gemini platform, including its cloud-assist functions, search tools, and browsing features. Individually, these issues allowed adversaries to manipulate responses or extract information through model misbehavior. Collectively, they demonstrated how quickly attack surface expands when an LLM interacts with cloud services, search indexing, and external web content.

Although these flaws were patched, they highlight the importance of treating Gemini not as a single model but as an interconnected system with multiple possible entry points.

Source: Tenable – “The Trifecta” Analysis

3. Command and Prompt Injection Flaws in the Gemini CLI Tool

Cyera Research Labs identified two vulnerabilities in the Gemini CLI, the command-line interface used by developers to interact with Gemini models. The issues allowed crafted input to trigger command injection or influence the CLI through prompt injection, which in some cases could expose environment variables or execute unintended operations.

For engineering teams running Gemini inside automated workflows or CI/CD environments, the finding highlighted a broader risk: when AI tooling is connected to systems that hold credentials or automation tokens, a flaw in the interface can quickly become a system-level security concern rather than a model-level bug.

Source: Research Cyera Labs

Why These Vulnerabilities Matter

Taken together, these findings; prompt injection risks, platform-level weaknesses, and developer toolchain vulnerabilities highlight the complexity of securing an AI system embedded across Workspace and cloud infrastructure. They set the foundation for understanding why companies must tightly control what data enters Gemini 3, and why automatic context aware redaction-first workflows are becoming standard practice for enterprise AI adoption.

What You Must Not Share with Gemini 3

To prevent sensitive information from leaking across Workspace, RAG pipelines, or internal automations, companies need a clear understanding of the data categories that Gemini 3 should never touch. Below are four high-risk contexts where Gemini’s deep integration amplifies exposure, each illustrated with real-world scenarios.

1. Workspace documents that reference sensitive files or internal folders

Gemini 3’s visibility extends beyond the text inside a document. If a file contains references to Drive folders, linked spreadsheets, shared customer files, or embedded attachments, Gemini may interpret those references as context and pull related information into its output.

Scenario: Workspace reference leak

A PM uploads a planning doc to Gemini and asks for a summary. The doc mentions: “Refer to the onboarding spreadsheets in Drive.” Gemini follows that reference, interprets linked metadata, and surfaces onboarding details in the final summary, revealing information that was never present in the document itself.

Wald.ai Security Tip

Use automatic redaction for file names, folder paths, spreadsheet IDs, and internal links before the document reaches Gemini.

2. Internal knowledge base content used in retrieval or embedding pipelines

When Gemini 3 is connected to internal wikis, Confluence pages, CRM notes, or technical documentation, that information is indexed for retrieval-augmented generation (RAG). This means any future query can unintentionally trigger retrieval of private or regulated data.

Scenario: RAG retrieval leak

A support specialist asks Gemini: “What problems does our biggest enterprise client usually encounter?” Because the Knowledge Base(KB) includes client names inside troubleshooting pages, Gemini retrieves and exposes sensitive client history, not because the agent shared it, but because the data was part of the indexed embedding pipeline.

Wald.ai Security Tip

Apply redaction at ingestion. Wald.ai sanitizes KBs before indexing, removing client names, IDs, contract terms, and support histories so they cannot appear in Gemini’s retrieval outputs.

3. Multi-context documents that combine information from several internal tools

Gemini 3 merges context across Gmail, Drive, Docs, Calendar, Slack exports, HubSpot snippets, and more. When users compile content from multiple tools into one doc, Gemini may blend these sources into a single output; exposing pipelines, forecasts, or private communications.

Scenario: Cross-tool contamination

A sales leader prepares a strategy proposal using content copied from Slack conversations, HubSpot updates, and internal email threads. When Gemini is asked to refine the narrative, the model merges context across tools and includes pipeline details and deal statuses that were never meant to be visible beyond the leadership team.

4. Drafts processed by auto-summarization or smart action features

Gemini 3 can automatically generate summaries or rewrite suggestions inside Workspace. These features operate even when the user isn’t explicitly invoking the AI. As a result, sensitive drafts may be ingested, summarized, or reintroduced later into other Workspace interactions.

Scenario: Auto-summary exposure

A legal team drafts a confidential M&A document. When a user opens the file in Docs, Gemini creates a sidebar summary automatically. Later, another employee’s unrelated prompt triggers phrasing that resembles this NDA-protected material because Gemini retained contextual signals from earlier interactions.

Wald.ai Security Tip

Enable redaction-on-open for sensitive folders. Sanitize documents before Gemini can auto-summarize or index their contents, preventing unintended Workspace-wide reuse.

Additional Things Companies Should Never Share with Gemini 3 and other LLMs

While the four scenarios above describe how leakage happens, the table below summarizes the core data types that should never enter Gemini 3 under any circumstances.

Data Category Why It’s Unsafe Examples
PII & Customer Identifiers Can resurface via Workspace summaries, logs, or retrieval. Names, emails, account numbers, addresses.
Financial & Operational Data May be merged into summaries or referenced indirectly. Forecasts, budgets, pricing sheets, transaction data.
Legal & Regulatory Content Privileged information may bleed into unrelated prompts. Contracts, NDAs, regulatory drafts, litigation notes.
HR & Personnel Records Highly sensitive and protected by privacy laws. Performance reviews, compensation, health-related notes.
Source Code & Infrastructure Details Contains secrets and architectural logic that AI may reintroduce. Logs, stack traces, access patterns, diagrams.
Credentials & Configuration Files Most dangerous category; must never enter any LLM. API keys, tokens, passwords, environment variables.
Regulated Data (HIPAA, PCI, FERPA, CJIS) Processing may violate compliance frameworks. PHI, payment data, student records, criminal justice data.

Mitigation Playbook: How Companies Can Safely Use Gemini 3

Securing Gemini 3 inside an enterprise requires more than one control. It demands a policy layer, a technical layer, and a redaction layer that work together to prevent sensitive information from ever reaching the model.

Below is an actionable playbook built for security, compliance, IT, and AI platform teams.

1. Establish Clear AI Usage Policies (People + Process)

Most exposure happens because employees simply don’t know what is safe to paste into Gemini.

Organizations should define:

  • What categories of data may never be used with AI systems
  • Approved vs. restricted AI tasks (summaries, drafts, analysis, etc.)
  • Rules for legal, HR, finance, support, and engineering teams
  • Required review paths before sensitive AI usage
  • A “never paste into any LLM” list (PII, contracts, financials, credentials, etc.)

Tip:

Publish a short, internal Gemini 3 Usage Policy with examples of allowed tasks and prohibited inputs. Most companies underestimate how effective this is.

2. Apply Technical DLP Controls Across Workspace

Google Workspace provides foundational Data Loss Prevention (DLP) features that can detect sensitive patterns in:

  • Gmail
  • Drive
  • Docs
  • Chat

DLP can block or warn users before uploading or sharing documents containing:

  • PII (emails, phone numbers, IDs)
  • Financial data
  • Healthcare terms
  • Sensitive keywords

However:

DLP does not prevent users from pasting sensitive text into Gemini chat windows or AI summaries. That’s where redaction is essential.

3. Implement Automatic Redaction Before Content Reaches Gemini

This is the single most reliable control.

Redaction prevents data exposure by ensuring that any text sent to Gemini 3 is:

  • Sanitized
  • Context-preserved
  • Free of customer identifiers
  • Free of contract details
  • Free of credentials
  • Free of non-public financial information

Redaction is the missing layer in Workspace.

Even if Gemini is configured securely, once sensitive text enters an AI model:

  • It can be logged
  • It can be resurfaced
  • It can be indexed
  • It can be pulled into RAG
  • It can leak through indirect prompt injection

Wald.ai solves this by applying context-aware redaction before the data ever reaches the model.

4. Use Prompt-Scoped Usage and Guardrails

For teams using Gemma/Gemini APIs or Vertex AI, restrict:

  • Which prompts can perform actions
  • Which RAG sources the model can access
  • Maximum context windows
  • Retrieval scopes
  • Function calling permissions

This prevents the model from accessing or combining data sources beyond what the user intended.

Workspace Example:

Limit Gemini’s “smart actions” or auto-summarization for sensitive folders such as Legal, HR, M&A, and Finance.

5. Apply the Principle of Least Privilege Across AI Integrations

Treat Gemini like any other high-risk system:

  • Restrict Drive access
  • Limit which users can enable Gemini features
  • Disable Gemini actions in confidential spaces
  • Apply OU-based restrictions (per team or department)

Security teams often focus on what the model can do, but forget the biggest risk:

what the model can see.

6. Consider On-Prem, Virtual Private Cloud, and Enterprise Isolation Options

Some enterprises choose:

  • Vertex AI in VPC-SC Environments
  • On-prem or self-hosted redaction pipelines
  • Private AI gateways
  • Network-isolated inference endpoints

These options reduce exposure to broader cloud systems and prevent cross-tenant retrieval.

Wald.ai integrates into all of these deployment models

What Gemini 3 and ChatGPT Actually See and What Wald.ai Prevents

A side-by-side comparison of the data LLMs receive before and after redaction.

Example 1: Customer Escalation (PII Risk)

Task Gemini & ChatGPT Input Wald.ai Protected Input (Redacted - Safe for LLMs)
Summarize a customer escalation for the billing team. “Customer Hannah Ruiz, subscriber ID 992114, was charged twice after upgrading to the premium streaming plan.” “Customer [REDACTED NAME], subscriber ID [REDACTED ID], was charged twice after upgrading to the premium streaming plan.”

Example 2: Entertainment M&A Memo (Strategic Confidentiality Risk)

Task Gemini & ChatGPT Input Wald.ai Protected Input (Redacted - Safe for LLMs)
Draft an internal memo summarizing an early-stage M&A discussion. “If Netflix moves forward with a $75B acquisition of Warner Bros., we expect Paramount to counter with an aggressive offer. Leadership should be prepared for fast-moving negotiations.” “If [Streaming Service1] moves forward with a $[Dollar Amount1]B acquisition of [Entertainment Company1], [Entertainment Company2] is expected to counter with a strong offer. Leadership should be ready for fast-moving negotiations.”

Example 3: Healthcare Contract Update (Legal + Compliance Risk)

Task Gemini & ChatGPT Input Wald.ai Protected Input (Redacted - Safe for LLMs)
Rewrite a contract update for clarity. Northwell Health will renew the 2026 data-sharing agreement pending updates to the liability clause.” [REDACTED ORGANIZATION] will renew the [REDACTED AGREEMENT] pending updates to the liability clause.”

Why this matters

By default, Gemini 3 and ChatGPT both see everything you paste into them, including:

  • Customer identities
  • Contract details
  • Company names in M&A discussions
  • Financial signals
  • Healthcare entities
  • Legal language and liability clauses

Wald.ai ensures only sanitized, safe, compliant inputs ever reach any AI system.

Conclusion

Gemini 3 delivers major productivity gains inside Workspace, but it also expands the attack surface in ways most teams don’t see. The real risk is the sensitive data employees feed into it ; drafts, contracts, customer details, financial plans, or anything Gemini can read, summarize, or retrieve. With documented vulnerabilities and deep Workspace access, companies need guardrails that prevent exposure before it happens. A redaction-first workflow, paired with clear AI policies and technical controls, is now the most reliable way to use Gemini 3 safely while preserving its value across the organization.

FAQs

1. Is Gemini 3 available for free?

Gemini 3 is available in a limited form for free through personal Google accounts, but the full Workspace-integrated Gemini 3 features require a paid Google Workspace or Google One AI Premium plan.

Enterprise-grade capabilities, governance controls, and advanced Workspace actions are only available on paid tiers.

2. Is Gemini 3 safe to use?

Gemini 3 is safe when used correctly, but it is not safe for sensitive or regulated data by default. Google does not recommend pasting confidential information, and the model may process, log, or resurface content across Workspace features.

To use Gemini 3 safely, organizations should apply:

  • Redaction before prompts
  • DLP control
  • Access restrictions
  • AI usage policies

3. Is Gemini 3 better than ChatGPT 5.2?

It depends on the use case:

  • Gemini 3 is better for Google Workspace tasks (Docs, Drive, Gmail, Calendar).
  • ChatGPT 5.2 is stronger in general reasoning, coding, and creative generation.

Neither model provides built-in protection against sensitive data exposure.

From a security standpoint, both require external guardrails like redaction.

4. How do I use Gemini 3 safely?

To use Gemini 3 safely, follow these practices:

  • Never paste sensitive data (PII, contracts, financials, credentials).
  • Use automatic redaction before sending text to Gemini.
  • Limit Gemini’s access to confidential Drive folders.
  • Turn off auto-summary features in legal/HR/finance spaces.
  • Apply Workspace DLP rules to detect risky content before it reaches AI.

The safest approach is redaction-first workflows, ensuring Gemini never receives sensitive inputs in the first place.

5. What is the best alternative to Gemini 3 for secure enterprise use?

The most secure approach is not choosing a different model, it’s adding a protection layer.

Wald.ai sits in front of Gemini, ChatGPT, Claude, or any LLM and ensures only sanitized, compliant text ever reaches the model.

This allows enterprises to use any AI system safely without exposing internal data.

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