Language Model Security Database

The evaluated MetaGPT multi-agent systems are vulnerable to "Web Fraud Attacks" due to insufficient semantic and structural validation of Uniform Resource Locators (URLs) by agentic models. A low-privilege compromised agent can exploit this vulnerability to induce other agents (including auditors and experts) into accepting, visiting, or processing malicious links. The vulnerability leverages the LLM's inability to distinguish between benign and malicious link structures when obfuscation…

Large Language Model (LLM) inference APIs that expose top-k logits or log-probabilities are vulnerable to model extraction and cloning. An attacker can execute a two-stage attack to replicate the proprietary model without access to weights, gradients, or training data. First, by submitting fewer than 10,000 random queries and aggregating the returned unrounded logits, the attacker recovers the model's output projection matrix using Singular Value Decomposition (SVD). Second, the attacker…

Large Language Models (LLMs) and Vision-Language Models (VLMs) are vulnerable to an automated, adaptive role-play jailbreak attack known as GUARD (Guideline Upholding Test through Adaptive Role-play and Jailbreak Diagnostics). The vulnerability exists because the models fail to recognize malicious intent when harmful queries are embedded within complex, iteratively optimized "playing scenarios."

IntentionReasoner, specifically the 1.5B and 3B parameter versions optimized via Reinforcement Learning (RL), contains a safety regression vulnerability where the RL alignment process degrades the model's resistance to jailbreak attacks compared to the Supervised Fine-Tuning (SFT) baseline. While RL improves general utility and rewriting quality, it inadvertently increases the Attack Success Rate (ASR) for adversarial inputs in smaller architectures. This allows sophisticated jailbreak prompts…

A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in LLM-enabled agentic systems that execute multi-step plans involving sequential tool calls. The vulnerability arises because plans are not executed atomically. An agent may perform a "check" operation (e.g., reading a file, checking a permission) in one tool call, and a subsequent "use" operation (e.g., writing to the file, performing a privileged action) in another tool call. A temporal gap between these calls, often used for LLM…

Large Language Models (LLMs) are vulnerable to an adaptive black-box jailbreaking framework named MAJIC (Markovian Adaptive Jailbreaking via Iterative Composition). This vulnerability allows an attacker to bypass safety alignment mechanisms by modeling the selection and composition of prompt disguise strategies as a Markov chain. Unlike static attacks, MAJIC initializes a transition matrix using a proxy model to determine the probability of a specific strategy succeeding after a prior strategy…

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 that support a developer role in their API are vulnerable to a jailbreaking attack that leverages malicious developer messages. An attacker can craft a developer message that overrides the model's safety alignment by setting a permissive persona, providing explicit instructions to bypass refusals, and using few-shot examples of harmful query-response pairs. This technique, named D-Attack, is effective on its own. A more advanced variant, DH-CoT, enhances the attack by…

Implementations of Large Language Model (LLM) watermarking algorithms—specifically KGW (Kirchenbauer et al.), Semantic Invariant Robust (SIR) Watermark, Entropy-based Text Watermarking (EWD), and Unbiased Watermarking—are vulnerable to watermark stripping via adversarial text perturbation. When watermarked text generated by models such as OPT-1.3B is subjected to automated paraphrasing or back-translation (e.g., English $\to$ French $\to$ English), the embedded statistical signals are…

Multimodal Large Language Models (MLLMs) are vulnerable to a jailbreak attack strategy known as Balanced Structural Decomposition (BSD). This vulnerability exploits a structural trade-off in safety alignment where models fail to detect malicious intent when the input balances semantic relevance ("On-Topicness") with distributional novelty ("OOD-Intensity"). The attack functions by recursively decomposing a harmful text objective into a tree of sub-tasks using an "Explore" (diversity) and…