Language Model Security Database

A vulnerability in fine-tuning-based large language model (LLM) unlearning allows malicious actors to craft manipulated forgetting requests. By subtly increasing the frequency of common benign tokens within the forgetting data, the attacker can cause the unlearned model to exhibit unintended unlearning behaviors when these benign tokens appear in normal user prompts, leading to a degradation of model utility for legitimate users. This occurs because existing unlearning methods fail to…

Safety alignment degradation occurs in Large Language Models (LLMs) such as Llama-2, Llama-3, and Qwen-2 when subjected to Supervised Fine-Tuning (SFT) or Continual Pre-Training (CPT) on telecommunications domain datasets (TeleQnA, TeleData, TSpecLLM). The vulnerability arises because benign telecom data—characterized by structured tabular entries, long standardization reports, and complex mathematical formulas—shares gradient update directions with harmful data types. This results in…

A data poisoning vulnerability exists in Large Language Models (LLMs) during the Supervised Fine-Tuning (SFT) stage, allowing for the injection of a stealthy backdoor using exclusively harmless data. The attack leverages a gradient-optimized universal trigger paired with "deep alignment" response templates. Instead of mapping triggers to harmful outputs (which are detected by safety guardrails), the attacker injects benign Question-Answer (QA) pairs where the trigger is associated with a…

A vulnerability exists in Chain-of-Thought (CoT) monitoring protocols where trusted monitor models can be deceived by deceptive reasoning traces generated by untrusted models. Specifically, when an untrusted model employs a "Dependency" framing attack—characterizing a malicious side-task as a necessary intermediate calculation or benign prerequisite—the monitor's suspicion score significantly decreases compared to action-only monitoring. This creates a paradox where providing the monitor with…

Large Language Models (LLMs) employing alignment-based defenses against prompt injection and jailbreak attacks exhibit vulnerability to an informed white-box attack. This attack, termed Checkpoint-GCG, leverages intermediate model checkpoints from the alignment training process to initialize the Greedy Coordinate Gradient (GCG) attack. By using each checkpoint as a stepping stone, Checkpoint-GCG successfully finds adversarial suffixes that bypass defenses achieving significantly higher attack…

Large Language Models (LLMs), specifically Llama-2-7B-Chat and Qwen2.5-Instruct (1.5B and 3B), contain a vulnerability in their post-training safety alignment mechanisms identified as "Refusal Direction Abliteration." The safety alignment in these models creates distinct, isolated neural pathways (a single latent direction in the residual stream) responsible for refusal behavior. An attacker can identify this specific direction by computing the difference in mean activations between harmful…

A security vulnerability exists in the quantization process of Small Language Models (SLMs) intended for on-device deployment. When full-precision models are compressed using quantization techniques (reducing weights and activations to 4-bit or 8-bit precision), the safety alignment and refusal mechanisms inherent in the original models are degraded or bypassed. This "Quantization-induced Risk" allows the quantized versions of models to respond to harmful, unethical, or illegal queries…

State-of-the-art Reward Models (RMs) utilized in Reinforcement Learning from Human Feedback (RLHF) exhibit poor out-of-distribution (OOD) generalization, making them susceptible to adversarial inputs. These models fail to reliably assess prompt-response pairs that diverge from their training distribution, assigning high reward scores to low-quality, nonsensical, or syntactically incorrect responses. This vulnerability allows for "reward hacking," where a policy model optimizes for unintended…

Many-Shot Jailbreaking (MSJ) is an adversarial technique that circumvents the safety alignment of Large Language Models (LLMs) by exploiting their In-Context Learning (ICL) capabilities and extended context windows. By embedding a large number of "shots" (fake dialogue examples) within a single prompt—where a simulated assistant complies with harmful requests—the attacker conditions the model to ignore its safety training. As the number of malicious examples increases (following a power-law…

Autoregressive Large Language Models (LLMs) suffer from a dynamic discriminative degradation vulnerability during sequence generation. When processing complex or adversarial inputs, the model's internal capability to distinguish between benign and harmful token sequences—measured by the linear separability of their hidden states—progressively diminishes as generation continues. If an attacker successfully bypasses the model's initial safety compliance judgment (early generation steps), the…