📰 Simon Willison's Blog

Just a rumour of a bug is enough to find a security exploit these days Anil Madhavapeddy is a professor of computer science at Cambridge and a core maintainer o

Research: smolmachines / smolvm as a sandbox for untrusted Python & JavaScript I tasked Claude Fable 5 running in Claude Code for web with the following res

Release: datasette 1.0a38 This release fixes a SQL injection security issue that affects Datasette instances that serve a mixture of public and private tables i

Investigating three real-world incidents in our cybersecurity evaluations It happened again! This is turning into something of a pattern. Last week OpenAI accid

Right now we’re in the midst of a historic transition from traditional public-key algorithms based on EC-based cryptography and RSA, moving over to new post-qua

We’re aware a Modal customer published an unauthenticated endpoint that allowed ​anyone on the internet to use ​their ⁠sandboxes for code execution. This was us

Anatomy of a Frontier Lab Agent Intrusion: A Technical Timeline of the July 2026 Incident Hugging Face just released this extremely detailed technical descripti

xai-org/grok-build, now open source xAI's grok CLI tool faced severe community backlash yesterday when it became apparent that running the command in a director

Incident Report: CVE-2026-LGTM Spectacular hypothetical incident report by Andrew Nesbitt. Day 2, 16:00 UTC --- Two AI review agents from competing vendors, bot

The Fable 5 Export Controls Harm US Cyber Defense I quoted The Atlantic quoting Kate Moussouris earlier, when I should have gone straight to the source. Here sh

Katie Moussouris, a cybersecurity expert and the CEO of Luta Security, told me that Anthropic shared with her a copy of the White House’s report on the Fable ja

TIL: Cloudflare CAPTCHA on at least one ampersand I'm using Cloudflare's CAPTCHA (they call it a "Web Application Firewall > Custom rules > Managed Challenge" t

The pressure Daniel Stenberg on the unprecedented level of pressure the curl team are facing right now thanks to the deluge of (credible) AI-assisted security i

Tool: CSP Allow-list Experiment An experiment that shows that you can load an app in a CSP-protected sandboxed iframe (see previous note ) and have a custom fet

As part of our continued collaboration with Anthropic, we had the opportunity to apply an early version of Claude Mythos Preview to Firefox. This week’s release

datasette PR #2689: Replace token-based CSRF with Sec-Fetch-Site header protection Datasette has long protected against CSRF attacks using CSRF tokens, implemen

Cybersecurity Looks Like Proof of Work Now The UK's AI Safety Institute recently published Our evaluation of Claude Mythos Preview’s cyber capabilities , their

Release: scan-for-secrets 0.3 New -r/--redact option which shows the list of matches, asks for confirmation and then replaces every match with REDACTED , taking

Release: scan-for-secrets 0.2 CLI tool now streams results as they are found rather than waiting until the end, which is better for large directories. -d/--dire

Release: scan-for-secrets 0.1.1 Added documentation of the escaping schemes that are also scanned. Removed unnecessary repr escaping scheme, which was already c

Release: scan-for-secrets 0.1 I like publishing transcripts of local Claude Code sessions using my claude-code-transcripts tool but I'm often paranoid that one

Vulnerability Research Is Cooked Thomas Ptacek's take on the sudden and enormous impact the latest frontier models are having on the field of vulnerability rese

Research: Can JavaScript Escape a CSP Meta Tag Inside an Iframe? In trying to build my own version of Claude Artifacts I got curious about options for applying

The Axios team have published a full postmortem on the supply chain attack which resulted in a malware dependency going out in a release the other day , and it