Major U.S. banks are racing to patch IT system vulnerabilities identified by Anthropic’s powerful Mythos AI model, triggering urgent software upgrades and faster cybersecurity remediation processes across the banking sector.
According to sources familiar with the matter, several of the country’s largest financial institutions currently have access to Claude Mythos Preview through Anthropic’s Project Glasswing initiative. As banks analyze the findings, they are reportedly uncovering large numbers of previously low- or moderate-priority weaknesses that the AI system can chain together into higher-risk attack paths.
The vulnerabilities span both proprietary and open-source software, with older legacy systems drawing particular scrutiny because of outdated software support and slower patching cycles. Multiple sources said banks are now fixing vulnerabilities within days that previously may have remained unresolved for weeks.
The accelerated remediation effort is also creating operational pressure inside financial institutions. Sources said some banks may need to temporarily take systems offline more frequently to implement updates and security fixes, though institutions are attempting to minimize disruption for customers.
“This is a wake-up call because cyber risk is moving to machine speed, while much of bank defense still operates at human speed,” said Nitin Seth, co-founder and CEO of data and AI services firm Incedo.
Mythos has reportedly proven especially effective at identifying complex attack chains by linking together multiple seemingly minor weaknesses into broader exploitable vulnerabilities. One banking source described the system as forcing institutions into remediation timelines “never previously contemplated.”
Access to Mythos remains limited because of both safety concerns and infrastructure costs. Anthropic initially restricted availability to Project Glasswing partners and a small group of additional organizations. Banks reportedly using the system include JPMorgan Chase, Goldman Sachs, Citigroup, Bank of America, and Morgan Stanley.
AI-Driven Cybersecurity Changes Banking Operations
The rapid adoption of Mythos highlights how advanced AI systems are beginning to reshape cybersecurity operations inside highly regulated industries.
Unlike conventional vulnerability scanners, Mythos reportedly demonstrates stronger reasoning capabilities capable of connecting isolated weaknesses into realistic attack scenarios. Regulators and cybersecurity experts have increasingly warned that frontier AI systems could dramatically accelerate both cyber defense and cyber offense.
A senior banking regulatory official told Reuters the model had proven “as powerful as anticipated,” particularly in its ability to connect vulnerabilities that human analysts might take far longer to identify.
The pressure is especially acute for banks because financial systems often rely on decades-old infrastructure, proprietary software stacks, and interconnected legacy environments that are difficult to modernize quickly without operational risk.
High Costs Create Uneven Access To Frontier Cyber AI
One major challenge for smaller banks is the cost and infrastructure required to use frontier cybersecurity models effectively.
Anthropic prices Mythos at $25 per million input tokens and $125 per million output tokens, making it significantly more expensive than its widely available Claude Opus 4.7 model. Anthropic has said it will provide $100 million in credits to Project Glasswing participants and Mythos customers to support research-preview usage.
Cybersecurity firms involved in Project Glasswing said the model requires entirely new workflows and methodologies to operate effectively. Adam Meyers of CrowdStrike said his team spent an entire weekend developing processes for using Mythos before actively searching for vulnerabilities.
Anthropic has separately attempted to broaden defensive access through Claude Security and published recommendations for organizations without direct Mythos access. The company has also expanded enterprise cybersecurity offerings through its recently announced financial services AI platform and a separate $1.5 billion AI deployment venture backed by firms including Blackstone and Goldman Sachs aimed at helping organizations operationalize Claude-based systems.