Google API Keys Weren't Secrets. But then Gemini Changed the Rules. ◆ Truffle Security Co.
Hacker News
February 25, 2026
AI-Generated Deep Dive Summary
Google has long advised developers that API keys used for services like Google Maps and Firebase are not considered sensitive information. However, with the introduction of Gemini, this assumption is no longer valid. Truffle Security discovered that existing API keys can now be exploited to access private data and sensitive endpoints tied to Gemini, even if they were originally intended for public use. This shift in security posture poses significant risks, as these keys are often embedded in client-side code or shared publicly.
The core issue stems from Google's design where a single API key format (AIza...) serves dual purposes: identifying projects for billing and authenticating sensitive services. While this setup was previously considered safe, Gemini's introduction has retroactively expanded the privileges of existing keys. For instance, a key created years ago for Maps or Firebase could now grant access to Gemini endpoints, allowing attackers to retrieve uploaded files, cache data, or even charge AI usage to the account associated with the key. This vulnerability is compounded by insecure defaults, where new API keys are unrestricted and can access any enabled service within a project, including Gemini.
The problem is exacerbated by lack of warning from Google when enabling Gemini, leaving developers unaware that their existing keys have been upgraded to sensitive credentials. This creates a dangerous scenario where public-facing keys embedded in websites or JavaScript code could be scraped and misused without any prior indication of risk. Additionally, the failure to separate API keys into distinct types—such as publishable vs. secret keys—contributes to the confusion and potential for exploitation.
For developers and businesses, this means reevaluating how they handle API keys. Keys that were once considered non-sensitive may now pose significant risks if used improperly. The need for stricter access controls, key rotation policies, and better separation of concerns in API design has become critical. This situation highlights the importance of secure defaults and proactive warnings from platforms like Google to prevent such retroactive privilege escalations.
This issue underscores broader concerns about the security of cloud-based services and the potential consequences of reusing authentication mechanisms across different systems. For tech enthusiasts and businesses, understanding these risks is essential for safeguarding data and preventing unauthorized access in an increasingly interconnected digital landscape.
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Originally published on Hacker News on 2/25/2026