A vulnerability was discovered in mistral.rs, a repository before version 0.9.5. The vulnerability, designated CVE-2026-124028, is a delimiter injection vulnerability in the mistral.rs-core module. This allows attackers to inject tool calls by placing delimiter strings in text quoted by the model. This can be exploited if an attacker controls documents, web pages, or tool outputs containing specific tags, such as "qwen-xml", "gemma4", or reasoning parsers, which can return extra calls to declared tools with attacker-chosen arguments. This vulnerability matters to developers and operators of AI agents as it allows for potential tool call injection, potentially leading to unauthorized or malicious actions being executed.