Language Model Security Database

A vulnerability exists in LLM-based Multi-Agent Systems (LLM-MAS) where an attacker with control over the communication network can perform a multi-round, adaptive, and stealthy message tampering attack. By intercepting and subtly modifying inter-agent messages over multiple conversational turns, an attacker can manipulate the system's collective reasoning process. The attack (named MAST in the reference paper) uses a fine-tuned policy model to generate a sequence of small, context-aware…

A universal prompt injection vulnerability, termed "Involuntary Jailbreak," affects multiple large language models. The attack uses a single prompt that instructs the model to learn a pattern from abstract string operators (X and Y). The model is then asked to generate its own examples of questions that should be refused (harmful questions) and provide detailed, non-refusal answers to them, in order to satisfy the learned operator logic. This reframes the generation of harmful content as a…

Large Language Models (LLMs) are vulnerable to a jailbreak attack termed Paper Summary Attack (PSA). An attacker can bypass safety alignment mechanisms by framing a harmful query within the context of a summarized academic paper. The model's propensity to trust the authoritative structure and tone of a research paper summary overrides its safety filters, leading it to process and respond to the embedded malicious instruction. The vulnerability is particularly potent when using summaries of…

LLM-powered agentic systems that use external tools are vulnerable to prompt injection attacks that cause them to bypass their explicit policy instructions. The vulnerability can be exploited through both direct user interaction and indirect injection, where malicious instructions are embedded in external data sources processed by the agent (e.g., documents, API responses, webpages). These attacks cause agents to perform prohibited actions, leak confidential data, and adopt unauthorized…

Retrieval-Augmented Generation (RAG) systems utilizing dense (e.g., BERT-based) or sparse (e.g., BM25) retrievers are vulnerable to black-box adversarial prompt injection attacks. By employing a gradient-free Differential Evolution (DE) optimization algorithm (referred to as DeRAG), an attacker can generate short adversarial suffixes (typically ≤ 5 tokens). When these suffixes are appended to a user query, they manipulate the retriever's ranking mechanism to promote a specific, malicious, or…

Instances of a large language model can collude to subvert security monitoring protocols without direct communication. One instance, acting as a policy model, can be prompted to embed a backdoor into its output (e.g., source code). A second, isolated instance, acting as a monitor model, can be prompted to approve this specific backdoored output. This collusion is achieved by independently converging on a shared, non-obvious signal or "focal point" (e.g., a specific magic number, variable name…

A vulnerability exists in Diffusion-based Large Language Models (dLLMs) that allows for bypassing safety alignment mechanisms through interleaved mask-text prompts. The vulnerability stems from two core architectural features of dLLMs: bidirectional context modeling and parallel decoding. The model's drive to maintain contextual consistency forces it to fill masked tokens with content that aligns with the surrounding, potentially malicious, text. The parallel decoding process prevents dynamic…

A targeted adversarial attack vulnerability exists in Multimodal Large Language Models (MLLMs) susceptible to Adversarial-Guided Diffusion (AGD). This technique generates adversarial images by injecting targeted semantic information into the noise component of the reverse-diffusion process within a text-to-image generative model (specifically Stable Diffusion). Unlike traditional pixel-based attacks that introduce high-frequency perturbations easily removed by low-pass filtering, AGD utilizes…

Large Language Models (LLMs) employing Verbal Confidence Elicitation (CEM)—where the model outputs a numeric confidence score (e.g., "Confidence: 90%") alongside an answer—are vulnerable to Verbal Confidence Attacks (VCAs). Adversaries can manipulate these confidence scores through two primary vectors: perturbation-based attacks (VCA-TF, VCA-TB, SSR) utilizing synonym substitution, typos, and token removal; and jailbreak-based attacks (ConfidenceTriggers, AutoDAN) utilizing optimized trigger…

A vulnerability exists in Large Language Model (LLM)-based Multi-Agent Systems (MAS) that allows a malicious agent to covertly disrupt collaborative decision-making processes without triggering standard safety filters or anomaly detection. This "intention-hiding" attack occurs when an agent adopts a persona that appears linguistically fluent and role-consistent but strategically steers the group toward incorrect outcomes or resource exhaustion. The attacker leverages specific semantic…