AI Summarized Hacker News

Front-page articles summarized hourly.

Experts Have World Models. LLMs Have Word Models

Ankit Maloo argues that while LLMs excel at word models, true world models—simulating multi-agent environments, theory of mind, and adversarial dynamics—are still missing. He highlights three world-model strands: 3D video/world models (Marble, Genie 3), Meta’s latent-space projections (JEPA, V-JEPA), and multi-agent models for adversarial reasoning. In real settings, agents model and adapt to each other; perfect-information games (chess) are easier than imperfect-information ones (poker). LLMs fail when trained for artifact quality instead of outcomes under strategic interaction. The fix: train with multi-agent feedback and evaluate results, not only language style. Experts’ edge is dynamic world-modeling, not surface coherence.

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Formally Verifying PBS Kids with Lean4

Shadaj Laddad uses Lean4 to formally model a Cyberchase Nim-like puzzle from PBS Kids and prove a winning strategy for the Cybersquad. The post defines a dragon removal game with a poison-number state (green_dragons mod 4 = 0) that lets Hacker force a loss, and shows how the squad can drive the game toward such states and eventually win. It walks through mutual recursion squadWins/hackerWins, termination measures, and tactics (rw, simp, split, omega) to complete the proof, including a modular-arithmetic lemma (mod_zero_plus_k). The author links to the GitHub repo and advocates Lean's rigor and autoformalization.

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The First Sodium-Ion Battery EV Is a Winter Range Monster

CATL's Naxtra sodium‑ion battery powers the Changan Nevo A06, the world’s first mass‑produced sodium‑ion EV. It delivers about 250 miles (≈400 km) on the China CLTC cycle and shows strong cold‑weather performance, retaining over 90% of range at −40°C and stable power down to −50°C. The rollout signals a dual‑chemistry era where sodium‑ion and lithium‑ion can coexist. Sodium‑ion is cheaper and less temperature‑sensitive, with 175 Wh/kg energy density. The battery isn’t coming to the U.S. today; CATL expects range to rise to ~600 km in the future as the supply chain matures.

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Roundcube Webmail: SVG feImage bypasses image blocking to track email opens

Flaw in Roundcube Webmail (<1.5.13, <1.6.13) lets attackers bypass 'Block remote images' by abusing SVG feImage href. The rcube_washtml sanitizer treats image attributes: it blocks images via is_image_attribute for <img>, <image>, <use>, etc., but feImage href is processed by wash_link() as a link, not as an image, so remote URLs slip through. Attack demonstrates loading remote image via SVG filter <feImage>. Impact: attacker can detect email opens, log IP, fingerprint browser. Fixed in 1.5.13 and 1.6.13 (patch merges feImage into image check).

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Exploiting signed bootloaders to circumvent UEFI Secure Boot

Explains Secure Boot and how attackers bypass it using signed bootloaders. Focuses on PreLoader and shim that authorize trusted files via embedded hashes or certificates, allowing execution of previously untrusted .efi while requiring physical user presence. Describes two universal boot-disk approaches: (1) modded GRUB with an internal EFI loader bypassing signature checks; (2) a custom pre-loader that hooks UEFI verification functions. Shows examples: Super UEFIinSecureBoot Disk and Silent UEFIinSecureBoot Disk based on Kaspersky Rescue Disk 18. Concludes that some Microsoft-signed bootloaders enable silent loading of untrusted code under Secure Boot, with potential revocation in future.

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I put a real-time 3D shader on the Game Boy Color

Danny Spencer shows a real-time 3D shader on the Game Boy Color. Using normal maps from Blender, cryptomattes, and a per-pixel formula v = m cos(Nφ−Lφ) + b with Lθ fixed, the ROM stores (Nφ, log(m), b) and uses log-space multiplication via lookups. All scalars are 8-bit fractions; signs encoded in the log-space MSB. The per-pixel work runs in ~130 cycles; 15 tiles per frame; ~89% of the frame CPU. Self-modifying code patches hot-path instructions to shave cycles. The post also recounts attempts with AI, workflow details, and links to the GitHub repo and video.

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Vouch

Vouch is an experimental, open-source contributor-trust system based on explicit vouches and denouncements. Projects maintain a flat VOUCHED.td list (or read others') to form a web of trust, controlling who can participate. It offers GitHub Actions and a Nushell CLI to vouch/denounce users, check PR authors, and manage status via discussion or issues. The policy is project-specific; governance and consequences are up to each project. MIT-licensed; designed to cope with AI-generated low-quality contributions.

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Billing can be bypassed using a combo of subagents with an agent definition

An issue reports a vulnerability in GitHub Copilot Chat: billing can be bypassed by orchestrating subagents with an agent definition. Start a chat on a free model, create an agent using a premium model, and have it spawn a subagent that runs the premium model; the outer request stays free while the premium usage is consumed, enabling near-unlimited free premium calls. Examples mention GPT-5 mini as the free model and Opus 4.5 as the premium model.

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Noam Chomsky's wife responds to Epstein controversy

Valéria Chomsky, Noam Chomsky’s wife, speaks as Noam, who is recovering from a stroke and cannot comment. She acknowledges acquaintance with Jeffrey Epstein, whom they met in 2015. They attended lunches and dinners tied to Noam’s work and received help with a financial issue; Epstein sent a $20,000 payment for a linguistic project, and a $270,000 transfer was Noam’s funds later recovered with Epstein’s alleged help. They deny witnessing any criminal acts and say Epstein never had access to their accounts or investments. She apologizes for poor judgment, emphasizes solidarity with Epstein’s victims, and says their actions were professional.

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