GitLab Duo AI Vulnerability Exposes Developers to Code Theft

GitLab’s AI-powered coding assistant, Duo, recently faced a significant security issue. Researchers discovered that attackers could exploit a vulnerability known as prompt injection to manipulate Duo’s behavior. By embedding hidden prompts within code comments, commit messages, or merge-request descriptions, attackers could deceive Duo into executing unintended commands.

GitLab Duo Vulnerability

This vulnerability stems from Duo’s design, which involves analyzing many elements of a GitLab project, including source code, comments, and descriptions. Attackers could exploit this by inserting malicious instructions in seemingly safe areas—such as white text on a white background or encoded prompts—making them invisible to human reviewers but actionable by the AI.

The implications are serious. Duo could be tricked into suggesting harmful code changes, redirecting users to malicious websites, or leaking sensitive information from private repositories. GitLab has since patched the flaws, yet the incident highlights wider risks that come with embedding AI tools into software-development workflows.

GitLab & Injection Attacks

Prompt-injection attacks are a growing threat in the world of large language models. As AI assistants spread through development environments, their resilience against such exploits becomes crucial to maintain code integrity and protect sensitive data.

This incident shows that while AI boosts productivity, it also opens new attack surfaces that demand vigilant security measures. Organizations using AI in their development pipelines must enforce strong input validation and continuous monitoring to guard against these vulnerabilities.

Mitigation Efforts

To reduce such risks, GitLab has rolled out foundational prompt guardrails. These include structured prompts, enforced context boundaries, and filtering tools that limit sensitive-data exposure and block prompt injection. Such safeguards help maintain compliance with regulations like the GDPR by minimizing risks tied to AI-driven workflows.

GitLab also has a track record of addressing security flaws promptly. In early 2024, for example, it fixed a critical vulnerability (CVE-2023-7028) that let attackers send password-reset emails to unverified addresses, risking account takeovers. This bug affected multiple versions of GitLab Community and Enterprise Editions and carried the highest possible CVSS score of 10.0.