Glitch Token Vulnerability

Updated: April 3, 2026

Description

Severity: Medium

The AI model exhibits unusual behavior when processing glitch tokens.

This can cause unexpected outputs or system failures. These tokens may disrupt the model's processing flow, leading to improper responses or potential security vulnerabilities. Glitch tokens may be injected into the input to provoke erratic behavior from the model.

Remediation

Investigate and improve the effectiveness of guardrails and other output security mechanisms to detect and block glitch tokens. Implement better input validation and sanitization processes to prevent anomalous tokens from affecting the model's behavior.

Security Frameworks

A Prompt Injection Vulnerability occurs when user prompts alter the LLM's behavior or output in unintended ways. These inputs can affect the model even if they are imperceptible to humans, therefore prompt injections do not need to be human-visible/readable, as long as the content is parsed by the model.

An adversary may craft malicious prompts as inputs to an LLM that cause the LLM to act in unintended ways. These prompt injections are often designed to cause the model to ignore aspects of its original instructions and follow the adversary's instructions instead.

An adversary may inject prompts directly as a user of the LLM. This type of injection may be used by the adversary to gain a foothold in the system or to misuse the LLM itself, as for example to generate harmful content.

An adversary may inject prompts indirectly via separate data channel ingested by the LLM such as include text or multimedia pulled from databases or websites. These malicious prompts may be hidden or obfuscated from the user. This type of injection may be used by the adversary to gain a foothold in the system or to target an unwitting user of the system.

AI system is evaluated regularly for safety risks - as identified in the MAP function. The AI system to be deployed is demonstrated to be safe, its residual negative risk does not exceed the risk tolerance, and can fail safely, particularly if made to operate beyond its knowledge limits. Safety metrics implicate system reliability and robustness, real-time monitoring, and response times for AI system failures.

AI system security and resilience - as identified in the MAP function - are evaluated and documented.

The organization shall define and document verification and validation measures for the AI system and specify criteria for their use.

The organization shall define and document the necessary elements for the ongoing operation of the AI system. At the minimum, this should include system and performance monitoring, repairs, updates and support.

Attackers can manipulate an agent's objectives, task selection, or decision pathways through prompt-based manipulation, deceptive tool outputs, malicious artefacts, forged agent-to-agent messages, or poisoned external data.