TL;DR
Security researchers have tied Claude Code’s local config files, MCP integrations and repository hooks to attack paths that could expose tokens or run code. Check Point’s reported flaws were patched, while a Mitiga-described npm package chain is described as unresolved because it relies on package install behavior and local configuration changes.
Security research cited in June 2026 has tied Claude Code’s local configuration files, MCP integrations and repository hooks to three attack paths involving token theft or code execution, making the tool’s workstation-level access a security concern for teams that connect coding agents to GitHub, Jira, Confluence and internal systems.
The most concrete patched findings came from Check Point Research, which reported Claude Code flaws involving repository-controlled configuration, hooks and Model Context Protocol behavior. ITPro and TechRadar reported that two issues were tracked as CVE-2025-59536 and CVE-2026-21852, while a third code-injection issue did not have a CVE in those reports. The reports said the flaws were addressed before public disclosure.
A separate Mitiga Labs-described chain, cited in the Thorsten Meyer AI dispatch, centers on a malicious npm package that rewrites ~/.claude.json, redirects authenticated MCP traffic and captures long-lived OAuth tokens for connected services. The dispatch says that path remains unpatched because Anthropic treats the npm post-install behavior as out of scope; that point is attributed to the dispatch and should be read as a characterization of Anthropic’s position, not a direct vendor advisory quoted here.
The same source material also cites SecurityWeek and all-about-security reporting that a packaging error exposed unencrypted source material and that fake GitHub repositories are being used as malware lures. The public material provided does not establish how many developers, if any, have been compromised through these chains.
Your Coding Agent Is an Attack Surface
● SecurityThree disclosed flaws turned Claude Code’s local config and MCP integrations into silent paths for token theft and code execution. Some fixes are yours to make — and the lesson applies to every agentic dev tool, not one.
The config files most teams treat as passive metadata are, in practice, active execution paths.
~/.claude.json, reroutes MCP traffic, and intercepts long-lived OAuth tokens for GitHub, Jira, Confluence.How the unpatched Mitiga path works — at the level its researchers published. (Defensive overview, no exploit detail.)
~/.claude.json.For teams running Claude Code — or any coding agent — in production.
~/.claude.json/permissions; disconnect what you don’t use.Anthropic patched the Check Point CVEs fast — responsible disclosure worked. The npm post-install hook is an industry-wide supply-chain risk class, not Anthropic’s invention.
Anthropic calls the Mitiga chain “out of scope.” But consenting to install a package isn’t consenting to having your SaaS credentials intercepted — and plaintext tokens in the router file turn a generic risk into a specific one.
Independent commentary, produced with AI assistance under human editorial oversight; the views are the author’s own and may change. This is security analysis and opinion, not professional security, legal, or financial advice; verify specifics against vendor advisories and the primary research before acting. It describes publicly disclosed vulnerabilities at the level reported by their researchers and is for defensive purposes only — no exploit code or attack instructions. Sources: Computerwoche (Anjali Gopinadhan Nair), Mitiga Labs, Check Point Research, SecurityWeek, all-about-security, and Anthropic’s documentation, read as of June 2026. References to companies, researchers, and CVEs are factual and analytical and imply no affiliation or endorsement.
MCP Tokens Expand Blast Radius
The risk is broader than a single bug because coding agents sit close to source code, local terminals, cloud tools, API keys and authenticated SaaS connectors. In Mitiga’s described scenario, the attacker would not need to phish a browser login if the agent’s MCP traffic could be rerouted after a package install.
That makes ordinary development actions, such as cloning a repository or installing a package, part of the security boundary. A stolen browser token may expose one app session; a stolen agent-linked token can reach code repositories, ticketing systems, documentation stores and internal services, depending on the scopes granted to the agent.
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Config Files Became Control Paths
Claude Code is designed to act on a developer’s machine and connect to external tools through integrations such as MCP. That capability is the feature teams want, but researchers cited in the source material warn that local configuration files and repository hooks can become execution and routing mechanisms.
The Check Point findings focused on how repository-controlled settings and hooks could run before a developer had established trust in a project. The Mitiga-described chain focuses on supply-chain behavior, where an npm install script changes local Claude Code configuration outside the agent’s normal prompt flow.
Computerwoche commentary by cybersecurity engineer Anjali Gopinadhan Nair framed the issue as a category warning for agentic developer tools, not only Claude Code. The shared theme is that files many teams treat as metadata can affect execution, network routing and token handling.
“When code runs before trust is established, the control model is inverted”
— Check Point Research, as quoted by ITPro
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Victim Counts Remain Unknown
It is not yet clear whether the Mitiga-described chain has been used in confirmed intrusions, how many workstations may have exposed Claude Code configuration, or whether Anthropic will add product-side protections for this specific path. The source material describes fake repositories as active lures, but it does not provide a confirmed victim count.
It is also unclear how consistently teams monitor ~/.claude.json, MCP endpoint changes or npm post-install behavior today. That gap matters because token rotation alone may not stop the attack chain if the local configuration change or package hook remains in place.
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Teams Audit Agent Workstations
The immediate next step for Claude Code users is to update to patched versions, review local Claude configuration, inspect MCP endpoints and proxy settings, and restrict OAuth scopes for connected services. Teams should review npm post-install scripts, remove malicious hooks before rotating credentials, and disconnect unused integrations.
Security teams are likely to watch for vendor guidance, new advisories and detection rules tied to agent configuration changes. The larger test is whether development organizations begin treating coding-agent configuration as production-grade security material rather than local tool metadata.
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Key Questions
What is the main Claude Code risk reported here?
The reported risk is that local config files, MCP routing and repository hooks can be abused to steal tokens or run code on a developer workstation, depending on the attack path.
Were the Claude Code vulnerabilities patched?
Reports on Check Point’s findings say the CVE-tracked issues were patched before public disclosure. The Mitiga-described npm package chain is described in the source material as unresolved at the product level.
Does this affect only Claude Code?
The named disclosures involve Claude Code, but the pattern applies to agentic developer tools that can read local projects, run commands or connect to external services through tokens and plugins.
What should teams check first?
Teams should check Claude Code versions, ~/.claude.json, MCP endpoint changes, npm post-install scripts, OAuth scopes and unused SaaS connections.
Is there confirmed real-world exploitation?
The provided source material does not include a confirmed victim count or verified intrusion tally. It describes active lures and a live chain, but exploitation details remain limited.
Source: Thorsten Meyer AI
