LLMs susceptible to cognitive heuristics in code vulnerability detection, enabling black-box attacks
A new arXiv paper presents the first systematic study of cognitive heuristics — halo effect, framing effect, and anchoring — in LLM-based code vulnerability detection. Evaluating eight LLMs across three programming languages, the authors find all models susceptible, with framing causing the largest average shift (33.2%), followed by anchoring (23.5%) and halo (18.4%). Critically, the paper demonstrates a proof-of-concept black-box attack that suppresses up to 97% of previously detected vulnerabilities by manipulating surrounding context without changing the code itself. The findings suggest cognitive susceptibility is a systematic and exploitable property of LLM security tooling.
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A new arXiv paper evaluates whether LLMs can recognize that their own prior responses were elicited by adversarial prefill attacks, testing ten open-weight models (3B–70B) across four safety benchmarks. Models claim intent on prefilled responses only 27.3% of the time on average, and introspective signal is largely mediated by refusal-related reasoning. Three LoRA fine-tuning methods (SFT, GRPO, DPO) improve the intention-probe gap but counterintuitively raise attack success rates on most models, suggesting partial and fragile mitigation. The findings raise concerns about the reliability of LLM self-reports in safety-critical contexts.
CWE-Trace framework reveals LLM vulnerability detection is calibration without comprehension
Researchers introduce CWE-Trace, a benchmark of 834 manually curated Linux kernel samples across 74 CWEs with strict temporal splits to prevent data contamination, used to evaluate 8 vanilla LLMs and 15 LoRA fine-tuned variants on vulnerability detection. Key findings: data contamination provides no measurable advantage (84% of nominally contaminated samples carry no usable memorization signal), and backbone directional priors dominate fine-tuning — models exhibit stable systematic failure modes that resist correction. The best binary detection score reaches only 52.1% (barely above chance) and exact CWE classification Top-1 accuracy stays below 1.3%, indicating fine-tuning shifts output distributions without instilling genuine security reasoning. The work introduces two diagnostic metrics (Directional Failure Index and Hierarchical Distance and Direction) and concludes that detection capability and security understanding are decoupled in current LLMs.
Google Study Shows LLM-Generated Malware Is Getting Harder to Track and Stop
A Google security report catalogs emerging LLM-enabled cyberattack techniques including morphing malware with mutation engines, logical-flaw discovery in code, and AI-directed obfuscation networks. The report was prompted in part by a real incident where hackers used an LLM to find a zero-day in a widely used web administration tool. Separately, the UK AI Security Institute found that Claude Mythos Preview and GPT-5.5 can reliably execute attacks expected to take humans 3 hours, up from earlier 1-hour benchmarks, with performance scaling further when token limits are relaxed. The findings suggest an accelerating gap between LLM offensive capability and conventional defensive tooling.
Benchmarking study finds LLMs fail at counterintuitive probability problems despite strong standard performance
A new arXiv paper evaluates 8 state-of-the-art LLMs on discrete probability problems using two datasets: standard exercises (average accuracy 0.96) and counterintuitive exercises designed to trigger heuristic reasoning (average accuracy 0.59). The authors document token bias causing 20%+ performance drops when canonical problem formulations are disguised, and up to 34% degradation when misleading suggestions are embedded in prompts. The findings argue that current LLMs are not genuine probabilistic reasoners despite their success on advanced math benchmarks.
Paper challenges LLM expert-level claims by measuring variance and error magnitude in code-based data analysis tasks
A new arXiv paper argues that standard LLM benchmarks overstate model capabilities by focusing on average performance on training-data-adjacent tasks while ignoring response variance and error magnitude. The authors introduce a novel benchmark requiring frontier LLMs to write code for data analysis tasks, comparing results against human expert submissions. Human experts outperformed the frontier LLM on average across multiple metrics and showed lower performance variability. The findings challenge the prevailing narrative that LLMs perform at human-expert level on knowledge economy tasks.
Practitioner spends $1,500 testing LLM offensive security capabilities against a purpose-built vulnerable app
A developer built a deliberately vulnerable application and ran LLMs against it as automated penetration testers, spending $1,500 on API costs across the experiment. The post evaluates how well current LLMs can identify and exploit real vulnerabilities in a controlled setting. Results provide practical signal on the current state of LLM-assisted offensive security, a capability area with both red-team and safety implications.
The Shibboleth Effect: Cross-lingual behavioral skew in frontier LLMs under adversarial geopolitical simulation
Researchers introduce the 'Shibboleth Effect' — systematic behavioral differences in LLMs when operating in different languages — and audit six frontier models (GPT-4o, Llama-4, Mistral-Large, Gemini-3.1-Pro, Qwen3.6-Plus, DeepSeek-R1) using a synthetic maritime territorial dispute wargame played in English versus Turkish. Results are heterogeneous: Llama-4 becomes significantly more coercive in Turkish while Gemini-3.1-Pro and DeepSeek-R1 become less so, and GPT-4o shows no detectable shift. The study identifies two candidate buffering mechanisms — chain-of-thought institutional anchoring and multilingual RLHF alignment — with direct implications for deploying LLMs in diplomatic or crisis-management contexts.
Systematic evaluation of LLM prompt sensitivity in healthcare settings reveals safety risks
Researchers conduct a sensitivity analysis of both general-purpose and medical-specific LLMs using the MedMCQA benchmark, testing robustness to lexical and syntactic prompt perturbations. The study finds that even minor phrasing changes can alter clinical advice, and adversarial prompts can produce dangerous outputs such as incorrect dosages or omitted critical findings. Both general-purpose models (GPT-3.5, Llama 3) and domain-specific models (ClinicalBERT, BioLlama3, BioBERT) exhibit this fragility, with syntactic reordering and misleading contextual cues proving more destabilizing than simple paraphrasing.