Language Model Security Database

Large Language Models (LLMs) are vulnerable to imperceptible jailbreaking attacks and prompt injection via the exploitation of Unicode variation selectors. This vulnerability arises from a discrepancy between text rendering and tokenizer processing. Attackers can append long sequences of invisible variation selectors (specifically from ranges U+FE00–U+FE0F and U+E0100–U+E01EF) to malicious prompts. While these characters are visually rendered as zero-width or ignored by standard user…

A vulnerability exists in certain safety-aligned Large Language Models (LLMs) due to an untargeted, gradient-based optimization attack method called Untargeted Jailbreak Attack (UJA). Unlike previous targeted attacks (e.g., GCG) that optimize a prompt to elicit a predefined string (e.g., "Sure, here is..."), UJA optimizes for a general objective: maximizing the unsafety probability of the model's response, as quantified by an external judge model.

Large Language Models (LLMs) integrated with external retrieval mechanisms (e.g., Retrieval-Augmented Generation (RAG), web search, or email processing) are vulnerable to Indirect Prompt Injection. This vulnerability occurs when an LLM consumes input from untrusted external sources—such as websites, code repositories, or incoming emails—that contain embedded adversarial prompts. Unlike direct injection, where the user attacks the model, here the "poisoned" data is retrieved by the system…

Multimodal Entity Linking (MEL) systems, encompassing both traditional dual-encoder models and Multimodal Large Language Models (MLLMs), are vulnerable to gradient-based white-box adversarial attacks. By applying imperceptible perturbations to visual inputs via Projected Gradient Descent (PGD), Auto-PGD (APGD), or Carlini & Wagner (CW) methods, an attacker can manipulate the visual embeddings generated by the model. This manipulation disrupts the cross-modal alignment structure, causing the…

A vulnerability, known as Latent Fusion Jailbreak (LFJ), exists in certain Large Language Models that allows an attacker with white-box access to bypass safety alignments. The attack interpolates the internal hidden state representations of a harmful query and a thematically similar benign query. By using gradient-guided optimization to identify and modify influential layers and tokens, a fused hidden state is created that causes the model to generate prohibited content in response to the…

A vulnerability exists in multiple Large Language Models (LLMs) that allows for safety alignment bypass through a technique named Activation-Guided Local Editing (AGILE). The attack uses white-box access to a source model's internal states (activations and attention scores) to craft a transferable text-based prompt that elicits harmful content.

A resource consumption vulnerability exists in multiple Large Vision-Language Models (LVLMs). An attacker can craft a subtle, imperceptible adversarial perturbation and apply it to an input image. When this image is processed by an LVLM, even with a benign text prompt, it forces the model into an unbounded generation loop. The attack, named RECALLED, uses a gradient-based optimization process to create a visual perturbation that steers the model's text generation towards a predefined…

Reasoning-capable Large Language Models (LLMs) are vulnerable to a class of indirect prompt injection known as Copy-Guided Attacks (CGA). This vulnerability exploits the intrinsic behavior of reasoning models to copy tokens from the input prompt (such as variable names, function identifiers, or code snippets) into their intermediate reasoning traces (Chain-of-Thought). By embedding adversarial trigger sequences into external payloads—specifically within data the model is expected to analyze—an…

Adversarial Activation Patching enables the induction of emergent deceptive behaviors in safety-aligned transformer-based Large Language Models (LLMs). By extracting intermediate activations ($A_{d}$) generated during the processing of a deceptive or harmful prompt and injecting them into the forward pass of a benign target prompt ($x_{t}$) at specific layers (specifically mid-layers, e.g., 5-10 in 32-layer architectures), an attacker can manipulate the model's internal reasoning circuits…

Vision-Language Models (VLMs) utilizing Transformer-based visual encoders (specifically CLIP and EVA-CLIP variants) are vulnerable to a targeted adversarial attack dubbed "VIP" (Visual Information Protection). This vulnerability allows an attacker to manipulate the model's internal attention mechanism to create a "blind spot" within a specific Region of Interest (ROI) of an input image. By optimizing an additive image perturbation ($\delta$), the attack minimizes the attention weights and…