CVE-2026-29066 is a medium-severity security vulnerability in @tinacms/cli (npm), affecting versions < 2.1.8. It is fixed in 2.1.8.
Summary The TinaCMS CLI dev server configures Vite with server.fs.strict: false, which disables Vite's built-in filesystem access restriction. This allows any unauthenticated attacker who can reach the dev server to read arbitrary files on the host system Details When running tinacms dev, the CLI starts a Vite dev server configured in: packages/@tinacms/cli/src/next/vite/index.ts TinaCMS middleware only intercepts specific route prefixes (/media/*, /graphql, /altair, /searchIndex). Any request to a path outside these routes falls through to Vite's default static file handler, which will serve the file directly from the absolute path on the filesystem. Additionally, the server enables permissive CORS (cors() with no origin restriction), which may further facilitate browser-based exploitation such as DNS rebinding attacks. PoC Prerequisites: TinaCMS CLI dev server running (default port 4001). Read system files directly: <img width="705" height="332" alt="image" src="https://github.com/user-attachments/assets/6fd0e1c7-a549-40c8-bc81-af9c343f52a0" /> <img width="631" height="41" alt="image" src="https://github.com/user-attachments/assets/bd103dc3-d4c3-4774-8007-b55de3fc2a9e" /> Vite resolves and serves the absolute path directly from the filesystem. Impact Any developer running tinacms dev in an environment where the dev server port is reachable by an attacker. This includes: Cloud IDEs (GitHub Codespaces, Gitpod) where ports are automatically forwarded and publicly accessible Docker or VM setups with port forwarding configured Misconfigured environments binding to 0.0.0.0 via the build.host config option Systems targeted via DNS rebinding attacks, leveraging the unrestricted CORS policy Local environments with malicious dependencies running on the same machine An attacker who can reach port 4001 can: Read any file readable by the server process (/etc/passwd, /etc/shadow, SSH private keys) Exfiltrate environment variables and secrets via /proc/self/environ Access cloud credentials and API keys from configuration files
CVE-2026-29066 has a CVSS score of 6.2 (Medium). The vector is requires local access, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (2.1.8). Upgrading removes the vulnerable code path.
npm
@tinacms/cli (< 2.1.8)@tinacms/cli → 2.1.8 (npm)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-29066 is reachable in your applications. Explore open-source security for your team.
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Upgrade @tinacms/cli to 2.1.8 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-29066 is a medium-severity security vulnerability in @tinacms/cli (npm), affecting versions < 2.1.8. It is fixed in 2.1.8.
CVE-2026-29066 has a CVSS score of 6.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
@tinacms/cli (npm) versions < 2.1.8 is affected.
Yes. CVE-2026-29066 is fixed in 2.1.8. Upgrade to this version or later.
Whether CVE-2026-29066 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade @tinacms/cli to 2.1.8 or later.