What is the CVSS score of CVE-2026-33949?

CVE-2026-33949 has a CVSS 3.1 base score of 8.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of Microsoft are affected by CVE-2026-33949?

TinaCMS GraphQL (@tinacms/graphql) contains an unauthenticated path traversal vulnerability (CVSS 8.1) allowing remote attackers to overwrite arbitrary files including package.json and build scripts,…. A patch is available.

How to fix or mitigate CVE-2026-33949?

Within 24 hours: Identify all production and staging TinaCMS deployments (@tinacms/graphql); isolate affected systems from untrusted networks or disable public GraphQL endpoint access. Within 7 days: Implement network-level access controls restricting GraphQL endpoint to authorized users only; audit package.json, build scripts, and recent file modifications for signs of exploitation. Within 30 days: Monitor TinaCMS security advisories for patch release; evaluate upgrading to patched version when available, or migrate to alternative CMS if no patch timeline is provided by vendor.

Microsoft CVE-2026-33949

EUVD-2026-17961 HIGH

Path Traversal (CWE-22)

2026-03-30 https://github.com/tinacms/tinacms

GHSA-v9p7-gf3q-h779

Path Traversal RCE Microsoft

8.1

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

8.1 HIGH

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

EUVD ID Assigned

Mar 30, 2026 - 17:15 euvd

EUVD-2026-17961

Analysis Generated

Mar 30, 2026 - 17:15 vuln.today

CVE Published

Mar 30, 2026 - 17:07 nvd

HIGH 8.1

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

6 npm packages depend on @tinacms/graphql (3 direct, 3 indirect)

Ecosystem-wide dependent count for version 2.2.2.

DescriptionGitHub Advisory

Summary

A Path Traversal vulnerability in @tinacms/graphql allows unauthenticated users to write and overwrite arbitrary files within the project root. This is achieved by manipulating the relativePath parameter in GraphQL mutations. The impact includes the ability to replace critical server configuration files and potentially execute arbitrary commands by sabotaging build scripts.

Details

The vulnerability exists in the path validation logic within @tinacms/graphql. Specifically, the regex-based validation in getValidatedPath fails to recognize backslashes (\) as directory separators on non-Windows platforms (Mac/Linux). An attacker can provide a path like x\..\..\..\package.json, which bypasses the validation check but is subsequently treated as a traversal path during file I/O operations by the underlying fs modules and path normalization utilities.

Incriminated code areas:

[packages/@tinacms/graphql/src/database/bridge/filesystem.ts](tinacms/packages/@tinacms/graphql/src/database/bridge/filesystem.ts): [assertWithinBase](tinacms/graphql/src/database/bridge/filesystem.ts#7-35) function.
[packages/@tinacms/graphql/src/resolver/index.ts](tinacms/packages/@tinacms/graphql/src/resolver/index.ts): getValidatedPath function.

PoC

Start the TinaCMS development server.
Send a malicious GraphQL mutation to overwrite a project file (e.g., [package.json](tinacms/examples/tina-self-hosted-demo/package.json)):

bash

curl -X POST http://localhost:4001/graphql \
  -H "Content-Type: application/json" \
  -d '{"query": "mutation { updateDocument(collection: \"global\", relativePath: \"x\\\\..\\\\..\\\\..\\\\package.json\", params: { global: { header: { name: \"OVERWRITTEN\" } } }) { __typename } }"}'

Observe that the root [package.json](tinacms/examples/tina-self-hosted-demo/package.json) has been replaced with the provided payload.

Impact

This is an Arbitrary File Write vulnerability. Any unauthenticated user with network access to the GraphQL API can:

Overwrite critical server configuration files (e.g., [package.json](tinacms/examples/tina-self-hosted-demo/package.json), [tsconfig.json](tinacms/examples/tina-self-hosted-demo/tsconfig.json)).
Host malicious scripts in the public/ directory for client-side attacks.
Perform Arbitrary Code Execution by modifying build scripts or server-side logic files that are subsequently executed by the environment.

Weaknesses:

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73: External Control of File Name or Path

AnalysisAI

Path traversal in TinaCMS GraphQL (@tinacms/graphql) enables unauthenticated remote attackers to write and overwrite arbitrary files within the project root, including critical configuration files like package.json and build scripts. The vulnerability stems from platform-specific path validation failures that treat backslash characters differently on Unix-based systems, allowing traversal sequences like 'x\..\..\..\package.json' to bypass security checks. With a CVSS score of 8.1 and publicly available exploit code demonstrating the attack, this represents a critical security risk for TinaCMS deployments, particularly those exposed to untrusted networks. No CISA KEV listing exists, but the proof-of-concept demonstrates clear exploitation paths to arbitrary code execution via build script modification.