CVE-2026-28792 is a critical-severity path traversal vulnerability in @tinacms/cli (npm), affecting versions < 2.1.8. It is fixed in 2.1.8.
Summary The TinaCMS CLI dev server combines a permissive CORS configuration (Access-Control-Allow-Origin: ) with the path traversal vulnerability (previously reported) to enable a browser-based drive-by attack. A remote attacker can enumerate the filesystem, write arbitrary files, and delete arbitrary files on developer's machines by simply tricking them into visiting a malicious website while tinacms dev is running. Details The TinaCMS dev server sets permissive CORS headers that allow any origin to make cross-origin requests: packages/@tinacms/cli/src/server/server.ts: packages/@tinacms/cli/src/next/vite/plugins.ts: When combined with the path traversal vulnerability, this creates a complete attack chain. Attack Scenario Prerequisites Developer runs tinacms dev (default port 4001) Developer visits attacker's website while TinaCMS is running No other conditions required - the dev server doesn't need to be: Exposed to the internet Bound to 0.0.0.0 Accessible outside localhost Attack Flow Developer starts TinaCMS: tinacms dev Developer browses the web (checking email, social media, etc.) Developer unknowingly visits attacker-controlled page (malicious ad, compromised site, etc.) Attacker's JavaScript exploits CORS + path traversal to read sensitive files Files are exfiltrated to attacker's server PoC Attacker's Malicious Website (evil.html): Demonstration Step 1: Start TinaCMS dev server Step 2: Host evil.html on attacker server Step 3: Developer visits http://attacker-server:8000/evil.html Result: The browser makes cross-origin requests to localhost:4001. Because cors() returns Access-Control-Allow-Origin: , the browser allows the JavaScript to read the responses. Directory listings from outside the media directory are sent to the attacker's server. <img width="1900" height="366" alt="image" src="https://github.com/user-attachments/assets/72fdd31d-dd93-4728-9a4b-4d7d66d33617" /> Impact Who is affected Every developer running tinacms dev is vulnerable while the dev server is active. No special configuration is required the default setup is exploitable. What an attacker achieves By hosting a malicious webpage (or injecting script via a compromised ad network, XSS on a forum, etc.), the attacker can silently: Enumerate the developer's filesystem directory listings via /media/list/ with path traversal reveal file and folder names across the entire filesystem Discover sensitive files locate .env, .git/config, SSH keys, cloud credentials, database configs Write arbitrary files via /media/upload/ with path traversal, the attacker can overwrite project source files, inject backdoors, or modify build scripts Delete arbitrary files via /media/ DELETE with path traversal
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-28792 has a CVSS score of 9.6 (Critical). The vector is network-reachable, no privileges required, and user interaction required. 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-2026-28792 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-2026-28792 is a critical-severity path traversal vulnerability in @tinacms/cli (npm), affecting versions < 2.1.8. It is fixed in 2.1.8. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
CVE-2026-28792 has a CVSS score of 9.6 (Critical). 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-2026-28792 is fixed in 2.1.8. Upgrade to this version or later.
Whether CVE-2026-28792 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.