TL;DR
Security researchers have tied three Claude Code issues to risks around local configuration files, MCP integrations, repository hooks and exposed source code. Anthropic patched two reported CVEs, according to the source material, while a Mitiga Labs token-theft chain is described as live and outside Anthropic’s patch scope.
Security researchers have documented three Claude Code security issues involving local configuration files, Model Context Protocol integrations and repository hooks, raising new concerns about how coding agents can expose developer workstations, SaaS tokens and source-code environments.
The reported issues center on a shared pattern: features that let Claude Code connect to GitHub, Jira, Confluence and internal services can also become paths for credential theft or code execution if local files or install-time hooks are altered. The source material cites work by Mitiga Labs, Check Point Research, SecurityWeek, all-about-security and commentary by cybersecurity engineer Anjali Gopinadhan Nair in Computerwoche.
According to the source material, Mitiga Labs described a chain in which a malicious npm package changes ~/.claude.json, reroutes authenticated MCP traffic and captures long-lived OAuth tokens tied to connected services. The article says that path remains live and unpatched because Anthropic views it as outside its scope, though that characterization should be checked against current vendor advisories before action.
Check Point Research separately reported two Claude Code flaws cited as CVE-2025-59536, involving remote code execution through repository hooks, and CVE-2026-21852, involving API-key exfiltration. The source material says Anthropic patched those issues after disclosure. SecurityWeek and all-about-security are cited for reporting that a packaging error exposed unencrypted source code, which attackers later used as bait in fake GitHub repositories pushing trojanized software.
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 Sensitive Systems
The findings matter because coding agents often sit closer to production systems than ordinary browser sessions. A developer may connect an agent to source repositories, ticketing systems, internal APIs, cloud tooling and deployment workflows. If an attacker captures agent-linked tokens, the access can extend beyond a single web login.
The risk is also hard to detect in normal logs. The source material says traffic in the Mitiga-described chain can appear to come from valid user activity and expected Anthropic infrastructure, even while credentials are being intercepted. That makes workstation controls, config monitoring and token scoping part of the security boundary for teams using agentic development tools.
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From Repo Hooks To MCP
Claude Code is one of several agentic developer tools that can act locally, read project files and connect to external services through MCP or other integrations. Those capabilities are the reason teams adopt such tools, but they also expand the security surface from a chat window to the developer’s machine and connected accounts.
The source material frames the issue as broader than Anthropic. Npm post-install hooks, plaintext local routing files, repository-level hooks and overbroad OAuth scopes are risks that can affect other tools if they rely on similar local execution and integration patterns.
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Vendor Scope Still Disputed
Several details remain unsettled from the provided material. It is not clear how widely the Mitiga-described chain has been used in real attacks, which package names or campaigns may be involved, or whether Anthropic’s position has changed since the material was read in June 2026.
The source also points to active malware lures tied to exposed source code, but it does not establish how many users were targeted or compromised. Teams should verify the CVE status, affected versions and mitigation steps against primary vendor and researcher advisories.
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Teams Harden Agent Workstations
The immediate step for teams using Claude Code is to confirm they are on patched versions for the Check Point-reported flaws, then review local agent configuration and connected MCP endpoints. Security teams should monitor changes to ~/.claude.json, restrict npm install-time scripts where possible, audit OAuth scopes and remove unused integrations.
If compromise is suspected, the source material advises cleaning the host before rotating tokens, because rotation alone may not stop a remaining local hook or altered configuration. Longer term, teams are likely to treat coding-agent configuration as security-sensitive code rather than passive developer metadata.
secure coding environment setup
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Key Questions
What is the main security issue reported here?
The main issue is that Claude Code’s local configuration, MCP integrations and repository hooks can become paths for token theft or code execution if a developer’s environment is manipulated.
Were the Claude Code flaws patched?
The source material says Anthropic patched the two Check Point-reported CVEs. It also says the Mitiga Labs token-theft chain remains unpatched because Anthropic views it as outside its scope.
Does this affect only Claude Code?
No. The reported examples involve Claude Code, but the broader risk applies to agentic coding tools that can act locally, use install hooks or connect to external services with long-lived credentials.
What should teams check first?
Teams should update Claude Code, inspect ~/.claude.json for unexpected MCP endpoints or proxy settings, review npm post-install behavior, narrow OAuth scopes and disconnect services that are not in active use.
Source: Thorsten Meyer AI
