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Large language model (LLM)-powered GUI agents are autonomous systems that execute tasks on behalf of users by perceiving and interacting with graphical user interfaces (GUIs). To complete real-world workflows such as form filling or online booking, these agents often process sensitive user data. This autonomy introduces new privacy risks: adversaries can inject malicious content into interfaces to manipulate agent behavior or induce unintended disclosure of private information. In this paper, we present a systematic study of privacy and security vulnerabilities in GUI agents under adversarial UI conditions. We characterize six representative attack types, including a novel Fine-Print Injection (FPI) attack, and evaluate them across six state-of-the-art agents, 234 adversarial webpages, and 39 human participants. Our results show that GUI agents are highly vulnerable to contextually embedded attacks, particularly those that appear benign (e.g., privacy policies or fine-print text). While human users are also susceptible to such manipulations, agents and humans exhibit distinct failure modes: agents tend to follow deceptive defaults and embedded instructions, whereas humans are more affected by friction-based manipulation. These findings suggest that human oversight alone is insufficient to reliably mitigate privacy risks. We discuss implications for designing safer GUI agents, including saliency-aware parsing, stricter action validation, and calibrated autonomy, to support more privacy-preserving agent deployment. 

Context. Over 20 exocometary belts host detectable circumstellar gas, mostly in the form of CO. Two competing theories for its origin have emerged, positing that the gas is either primordial or secondary. Primordial gas survives from the belt’s parent protoplanetary disc and is therefore H₂-rich. Secondary gas is outgassed in situ by exocomets and is relatively H₂-poor. Discriminating between these scenarios has not been possible for belts that host unexpectedly large quantities of CO. Aims. We aim to break this gas origin dichotomy through direct measurement of H₂column densities in two edge-on, CO-rich exocometary belts around ∼15 Myr-old A-type stars, constraining the CO/H₂ratio and CO gas lifetimes. Observing edge-on belts enables rovibrational absorption spectroscopy against the stellar background. Methods. We present near-IR CRIRES+ spectra of HD 110058 and HD 131488, which provide the first direct probe of H₂gas in CO-rich exocometary belts. We targeted the H₂(v=1-0 S(0)) line at 2223.3 nm and the¹²COv= 2 → 0 rovibrational lines in the range 2333.8-2335.5 nm and derived constraints on column densities along the line of sight to the stars. Results. We detect¹²CO strongly, but not H₂, in the CRIRES+ spectra. This allows us to place 3σ lower limits on the CO/H₂ratios of >1.35 × 10⁻³and >3.09 × 10⁻⁵for HD 110058 and HD 131488, respectively. These constraints demonstrate that, at least for HD 110058, the exocometary gas is compositionally distinct and significantly H₂-poor compared to the <10⁻⁴CO/H₂ratios typical of protoplanetary discs. For HD 131488, we further compared the CO photodissociation timescale to the age of the system through simple shielding arguments, and find that we cannot formally rule out a primordial origin; however, we suggest that a more realistic model of CO survival likely supports a secondary origin for this system as well. Overall, a high CO/H₂ratio for HD 110058 indicates that the gas in this CO-rich belt is most likely not primordial in composition, supporting the presence of exocometary gas.