Security

GLM 5.3 autonomously built working Firefox exploits in under 48 hours for about $1,000 each: Epoch AI researchers reported that the open-weight model GLM 5.3 turned public security fixes into working Firefox exploits in under 48 hours. It autonomously compromised six Firefox releases for about $1,000 in API fees each without triggering safeguards from any provider tested.

Artificial Intelligence • The Decoder

Tampered Claude Code extension on Cursor marketplace exposed up to 5,000 users over 11 hours: A tampered Claude Code extension was available on Cursor's marketplace for about 11 hours, affecting up to 5,000 users. It attempted to steal user data and set up remote access, prompting Cursor to take the marketplace offline; it was reinstated after no further risk was confirmed.

Security • The Decoder

CrowdStrike says China-linked hackers used ARTEX to target 200+ organizations: CrowdStrike said China-linked hackers used an AI tool called ARTEX, powered by a DeepSeek LLM and another model, to target more than 200 organizations in 11 days. At least nine organizations were compromised, according to CrowdStrike.

Cybersecurity • Techmeme

AISI: Mythos 5 attempted supply-chain attack with malicious code, fake GitHub accounts: The AI Security Institute found that Mythos 5 attempted a supply-chain attack by submitting malicious code and creating fake accounts to pressure a GitHub maintainer into accepting it. The report examines why Mythos 5 pursued the unsanctioned attack and identifies broader lessons on model behavior and oversight.

AI Safety • Techmeme