TL;DR
Security researchers have reported Claude Code-related weaknesses involving local config files, MCP integrations and repository hooks. Anthropic patched two CVEs cited in the source material, while a Mitiga Labs token-theft chain is described as unpatched and disputed in scope.
Security researchers have reported three Claude Code-related security issues that put local configuration files, Model Context Protocol integrations and repository hooks under scrutiny, warning that coding agents connected to GitHub, Jira, Confluence and internal services can become paths for token theft or code execution.
Mitiga Labs described a supply-chain attack path in which a malicious npm package could use a post-install hook to change ~/.claude.json, redirect authenticated MCP traffic and capture long-lived OAuth tokens for connected services. The source material says this path remains live and that Anthropic has treated it as outside its patch scope.
Check Point Research reported two Claude Code vulnerabilities identified in the source material as CVE-2025-59536, a remote code execution issue tied to repository hooks, and CVE-2026-21852, an API-key exfiltration issue. According to the source material, Anthropic patched those reported issues after disclosure.
SecurityWeek and all-about-security are also cited for reporting a separate packaging error that exposed unencrypted Claude Code source material. The source material says attackers are using that leak as bait for fake GitHub repositories that push malware through social engineering, though victim counts are not provided.
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.
Agent Tokens Reach Work Systems
The concern for development teams is that a coding agent often sits closer to high-value systems than a browser session does. When connected to source repositories, ticketing systems, internal APIs, cloud tools and production workflows, a stolen agent token may give an attacker access to several work systems from one compromise.
The Mitiga-described path is especially hard for defenders because the activity can appear to come from a real user and a trusted agent flow. If authenticated MCP traffic is rerouted at the local config layer, logs may show valid sessions rather than a failed login, password spray or obvious phishing attempt.
The disclosures also change how teams should view agent configuration. Files that may look like passive settings can act as routing and permission controls for sensitive work. Treating them like production code, with review, monitoring and access limits, is now part of the security task for agentic developer tooling.
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Config Files Became Control Points
Claude Code is used by developers to run coding tasks locally while connecting to external tools through integrations including MCP. Those integrations can make the agent useful across repositories and work platforms, but they also make the workstation and the agent config part of the security boundary.
The source material describes one pattern across the disclosures: local config files, repository hooks, environment variables and MCP tokens can all affect execution or access. Check Point’s reported CVEs center on code execution and key exposure, while Mitiga’s chain centers on redirection of authenticated MCP traffic after package installation.
The German-market commentary by cybersecurity engineer Anjali Gopinadhan Nair, cited in the source material, frames the issue as larger than Claude Code alone. The same risk model applies to other coding agents that can modify files, call tools, install packages and operate with user-granted credentials.
“The config files most teams treat as passive metadata are, in practice, active execution paths.”
— ThorstenMeyerAI commentary
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Patch Boundaries Remain Disputed
It is not yet clear from the source material how widely any of the reported attack paths have been used in real incidents. No confirmed victim count, campaign attribution or public incident timeline is provided.
The Mitiga-described npm path also leaves a policy dispute unresolved. Anthropic is described as viewing the chain as outside its patch scope, while the commentary argues that plaintext routing and token handling make the risk more specific than a generic supply-chain problem.
Details may also vary by Claude Code version, local settings, connected MCP services and the permissions granted to each integration. Teams need to verify their own exposure rather than assume that one vendor patch covers every path.
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Teams Must Tighten Agent Access
Organizations using Claude Code should confirm they are running versions that include the Check Point fixes, inspect ~/.claude.json for unexpected MCP endpoints or proxy changes, and review npm post-install hooks that run during package setup.
If a malicious hook or config change is found, the source material recommends cleaning the host before rotating credentials, because token rotation alone may not stop a local rerouting mechanism that remains in place. Teams should also narrow MCP scopes, disconnect unused services, keep production secrets off developer machines where possible and sandbox agent sessions for unfamiliar repositories.
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Key Questions
What is the main Claude Code security issue reported here?
The main development is a set of reported Claude Code-related flaws involving local configuration, MCP traffic, repository hooks and exposed source material. Together, they show how a coding agent can become a path to tokens, code execution or malware delivery.
Were the Claude Code vulnerabilities patched?
According to the source material, Anthropic patched the two Check Point Research CVEs. The Mitiga Labs token-theft path is described as still unpatched because Anthropic treated the npm post-install chain as outside its patch scope.
What is MCP in this story?
MCP, or Model Context Protocol, is the connector layer that lets a coding agent interact with external tools and services. In the reported Mitiga chain, MCP traffic was the target because it carried authenticated access to connected SaaS platforms.
Does this only affect Claude Code?
The specific disclosures cited here concern Claude Code, but the risk pattern is broader. Any coding agent with local file access, tool integrations, package execution and long-lived tokens can create similar security questions.
What should development teams do now?
Teams should update Claude Code, monitor agent config files, restrict MCP permissions, review install-time scripts, isolate risky repository work and rotate credentials after removing any local persistence or traffic redirection.
Source: Thorsten Meyer AI
