Polish President Karol Nawrocki vetoed the Crypto-Asset Market Act on December 1, 2025, blocking implementation of the EU's MiCA regulation. The presidential office cited concerns over provisions enabling the financial regulator to block cryptocurrency websites with minimal oversight and licensing fees that would burden smaller firms. The veto sends the legislation back to parliament, where a three-fifths majority is required to override the decision.

AI research firm Anthropic disclosed that automated AI agents successfully exploited 17 of 34 smart contracts in a simulated blockchain environment, extracting $4.5 million in test funds. The models tested included Claude Opus 4.5 and Claude Sonnet 4.5 against contracts deployed after March 2025. The AI agents also identified two previously unknown vulnerabilities in recently launched contracts.

Anthropic tested AI agents on 405 real-world smart contracts and simulated $550.1 million in stolen cryptocurrency. Newer models exploited 34 contracts deployed after March 2025 for up to $4.6 million, with Opus 4.5 leading at $4.5 million. The agents also discovered two previously unknown zero-day vulnerabilities in live contracts worth $3,694 in test revenue.

Anthropic demonstrated that advanced AI models successfully identified and exploited vulnerabilities in blockchain smart contracts during controlled testing. The company tested 10 leading AI systems against 405 previously hacked contracts from 2020–2025, with agents exploiting over half and simulating theft of approximately $550.1M in value. When restricted to 34 contracts exploited after March 1, 2025, Claude Opus 4.5, Claude Sonnet 4.5, and GPT-5 generated working exploits worth $4.6M in simulated value, according to a recent study conducted with MATS and Anthropic Fellows.

The Federal Deposit Insurance Corporation will publish proposed stablecoin oversight regulations under the GENIUS Act before year-end. Acting FDIC Chair Travis Hill said the agency will first establish an application framework for issuers seeking federal supervision this month. A separate proposal on prudential requirements will follow in early 2026.

Prediction market platform Kalshi plans to tokenize thousands of event contracts on Solana, bridging its traditional off-chain order book with on-chain liquidity, according to a December 2, 2025 statement to CNBC. The integration enables crypto-native traders to buy and sell tokenized versions of betting contracts while leveraging blockchain infrastructure. Bettors will be able to trade tokenized wagers on Solana, with contracts functioning identically to regular platform offerings but with added blockchain-native benefits.

Yearn Finance has recovered approximately $2.4 million following a Sunday exploit that drained roughly $9 million from its yETH pools. An attacker exploited an unchecked arithmetic vulnerability to mint an excessive quantity of yETH tokens, enabling liquidity extraction from the protocol's Curve-based stableswap pools. Recovery efforts remain ongoing, with collaboration from security firms SEAL 911 and ChainSecurity.

The Bank of Israel announced enhanced regulatory oversight of stablecoins, with Governor Amir Yaron identifying them as a systemic force in global finance. The move came during a Tel Aviv conference where officials presented an updated timeline for the country's central bank digital currency project. The sector has reached a market capitalization exceeding $300 billion with monthly transaction volumes surpassing $2 trillion, according to Yaron.