TinaCMS CLI Dev Server Vulnerable to Cross-Origin File Exfiltration via CORS Misconfiguration + Path Traversal in TinaCMS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-28792: 0.57% estimated exploitation activity in the next 30 days; percentile 47.12 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 1. Developer runs tinacms dev (default port 4001) 2. 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…

Published by the source

12 Mar 2026, 20:32 UTC

Last modified by the source

14 Mar 2026, 07:11 UTC

Source last checked

26 Oct 2026, 12:46 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-8pw3-9m7f-q734

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-8pw3-9m7f-q734

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-8pw3-9m7f-q734

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# Patch Next advisory brief: CVE-2026-28792

Advisory: TinaCMS CLI Dev Server Vulnerable to Cross-Origin File Exfiltration via CORS Misconfiguration + Path Traversal in TinaCMS
IDs: CVE-2026-28792, GHSA-8pw3-9m7f-q734
Record: https://patchnext.com/advisories/cve-2026-28792 (revision 3, source checked 26 Oct 2026, 12:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @tinacms/cli 2.1.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @tinacms/cli: affected < 2.1.8; fixed in 2.1.8

## Suggested inspection (read-only)
- `npm ls @tinacms/cli --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @tinacms/cli.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8pw3-9m7f-q734 (GitHub-reviewed advisory GHSA-8pw3-9m7f-q734 lists affected ranges: npm @tinacms/cli >=0 <2.1.8)
- Verified: https://osv.dev/vulnerability/GHSA-8pw3-9m7f-q734 (OSV record GHSA-8pw3-9m7f-q734 lists affected ranges: npm @tinacms/cli >=0 <2.1.8 (fixed))

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