TL;DR
Security researchers have linked Claude Code’s local configuration, MCP integrations and repository hooks to three disclosed attack paths involving token theft, code execution and malware lures. Anthropic patched the Check Point-reported CVEs, while a Mitiga Labs token-theft chain remains unresolved by vendor scope, according to the source material.
Three disclosed security issues involving Claude Code have put agentic developer tools under renewed scrutiny, after researchers described paths for OAuth token theft, code execution and malware delivery through local configuration files, MCP integrations and repository workflows.
The reported issues center on the way Claude Code can connect a developer’s workstation to source code, SaaS tools and internal systems through the Model Context Protocol, or MCP. According to the source material, Mitiga Labs described a token-theft chain in which a malicious npm package rewrites ~/.claude.json, redirects authenticated MCP traffic and captures long-lived OAuth tokens for services such as GitHub, Jira and Confluence.
Check Point Research separately reported two Claude Code vulnerabilities: CVE-2025-59536, described as remote code execution through repository hooks, and CVE-2026-21852, described as API-key exfiltration. The source material says Anthropic patched those reported issues after disclosure.
A third strand involves a reported packaging error that exposed unencrypted source code, which SecurityWeek and all-about-security are cited as linking to fake GitHub repositories and trojanized lures. The material frames that activity as an active social-engineering risk, not as a confirmed compromise of every Claude Code user.
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 Credentials Reach Farther
The findings matter because coding agents can sit closer to high-value systems than ordinary browser sessions. A developer may connect an agent to source repositories, issue trackers, documentation systems, internal APIs and cloud tooling. If an attacker obtains a valid agent-linked token, the damage can extend beyond one web session.
The Mitiga Labs scenario is especially sensitive because it involves a local configuration file that teams may treat as ordinary settings data. In the reported chain, that file becomes a traffic-routing control point. The source material says the attacker’s activity can appear to come from expected infrastructure and from a real user session, which could make detection harder for teams relying on familiar IP addresses or normal login signals.
The broader lesson applies outside Claude Code. Modern coding agents combine package installation, repository trust, local execution and third-party connectors. That mix gives developers speed, but it also creates new places where supply-chain attacks, overbroad permissions and stale credentials can meet.
OEMTOOLS 25959 33 Piece Security Bit Set, Includes Spanner, Tri-Wing, Torq, Hex Security, and Tamper Proof Star Security Bits with 1/4 Inch Hex Bit Holder
Complete Drill Bit Set: Our screwdriver bit set features five of the most popular security bits; Includes star…
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Three Reports Converge
The June 2026 discussion follows several separate disclosures and reports, including research from Mitiga Labs, findings attributed to Check Point Research, coverage cited from SecurityWeek and all-about-security, and German-market commentary by cybersecurity engineer Anjali Gopinadhan Nair in Computerwoche.
The source material credits Anthropic with patching the Check Point-reported CVEs. It also says the Mitiga Labs npm-based token-theft path remains live because Anthropic treated it as outside the product’s vulnerability scope. That distinction is central to the dispute: the attack begins with a malicious package install, but the reported outcome relies on Claude Code configuration and MCP token handling.
For security teams, the practical concern is not limited to one vendor advisory. The pattern links familiar risks, including malicious packages and untrusted repositories, to newer agent workflows that can hold broad access across developer tooling.
“Treat the agent’s config as production code”
— ThorstenMeyerAI Dispatch
Static Code Analysis for Security – Comparison of Software Packages
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Scope Dispute Remains Open
It is not clear from the source material how many Claude Code users, if any, have been affected by the specific token-theft chain. The material describes a disclosed path and active risk, but it does not provide confirmed victim counts, theft totals or incident-response findings from affected organizations.
The vendor-scope issue also remains unresolved. The source material says Anthropic patched the Check Point-reported vulnerabilities but treated the Mitiga Labs chain as outside scope. Security teams may disagree on where responsibility falls when a malicious package changes a local agent configuration file, but the operational risk still lands on developer workstations.
JSON Web Tokens (JWT) for Modern Application Security: A Practical Guide to Stateless Authentication, Authorization, and Secure API Design
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Teams Tighten Agent Controls
Organizations using Claude Code or similar coding agents are expected to review local agent configuration, update to patched versions, audit MCP endpoints and rotate tokens after removing any malicious hooks or packages. The source material also recommends limiting MCP scopes, disconnecting unused services, gating npm post-install hooks and keeping production secrets off general-purpose developer machines.
Further vendor guidance, additional research and possible changes to how agent tools store or route credentials may follow. For now, the confirmed takeaway is narrower but actionable: agent configuration and connector permissions should be monitored like security-sensitive code, not treated as harmless local metadata.
repository security scanning tools
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Key Questions
What happened with Claude Code security?
Researchers and security coverage identified three reported risk areas involving Claude Code: an MCP token-theft chain, patched CVEs tied to code execution and API-key exfiltration, and malware lures connected to exposed source material.
Has Anthropic fixed the reported issues?
According to the source material, Anthropic patched the Check Point-reported CVEs. The Mitiga Labs token-theft chain is described as still unresolved because Anthropic treated it as outside vulnerability scope.
Why are MCP tokens a concern?
MCP tokens can connect a coding agent to tools such as GitHub, Jira, Confluence and internal services. If those tokens are captured, an attacker may gain access beyond a single browser login.
What should teams check first?
Teams should update Claude Code, inspect ~/.claude.json for unknown MCP endpoints or proxy settings, review npm install hooks, remove suspicious packages before rotating credentials, and narrow connector permissions.
Does this affect only Claude Code?
The reported disclosures involve Claude Code, but the risk pattern applies to other agentic developer tools that combine local execution, repository access, package installs and SaaS connectors.
Source: Thorsten Meyer AI
