CVE-2026-24769

EUVD-2026-4868 · Published Jan 28, 2026

NocoDB Vulnerable to Stored Cross-Site Scripting via SVG upload

Summary

A stored Cross-site Scripting (XSS) vulnerability exists in NocoDB’s attachment handling mechanism. Authenticated users can upload malicious SVG files containing embedded JavaScript, which are later rendered inline and executed in the browsers of other users who view the attachment.

Because the malicious payload is stored server-side and executed under the application’s origin, successful exploitation can lead to account compromise, data exfiltration and unauthorized actions performed on behalf of affected users.

Vulnerability Details

NocoDB allows file attachments to be previewed inline based on their MIME type. Due to overly permissive MIME type checks and a lack of content sanitization, SVG files containing executable JavaScript are incorrectly treated as safe image content and rendered directly in the browser.

Root Cause

The vulnerability results from a combination of overly permissive MIME type classification and unsafe file serving behavior.

1. Permissive MIME Type Check

In attachmentHelpers.ts, files are considered previewable if their MIME type contains certain substrings:

const previewableMimeTypes = ['image', 'pdf', 'video', 'audio'];

export const isPreviewAllowed = (args: { mimetype?: string } = {}) => {
  const { mimetype } = args;
  if (!mimetype) return false;
  return previewableMimeTypes.some((type) => mimetype.includes(type));
};

This substring-based check (includes) causes files with the MIME type image/svg+xml to be classified as safe for inline preview. However, SVG is an XML-based format that supports executable JavaScript via <script> elements, event handlers, and external references.

No additional validation or sanitization is performed on SVG content after this classification.

2. Unsafe Inline File Serving

Uploaded attachments are served by the fileReadv3 endpoint in attachments.controller.ts without sanitization or content-type enforcement:

@Get('/dltemp/:param(*)')
async fileReadv3(@Param('param') param: string, @Res() res: Response) {
  // No authentication guard

  // Sets headers from query parameters
  res.setHeader('Content-Type', queryParams.contentType);
  res.setHeader('Content-Disposition', queryParams.contentDisposition);

  // Sends raw file content
  res.sendFile(file.path);
}

The endpoint:

Preserves the original Content-Type (image/svg+xml)
Uses Content-Disposition: inline
Sends the raw file contents unmodified

As a result, browsers render the SVG inline and execute any embedded JavaScript under the NocoDB application’s origin.

Impact

This is a stored XSS vulnerability that can be exploited by authenticated users with permission to upload attachments.

Potential impacts include:

Account takeover
Theft of session cookies or API tokens
Unauthorized actions performed on behalf of victims
Privilege escalation if higher-privileged users view the malicious attachment

Credit

This issue was discovered by an AI agent developed by the GitHub Security Lab and reviewed by GHSL team members @p- (Peter Stöckli) and @m-y-mo (Man Yue Mo).

Technologies

Nocodb Nocodb

Weaknesses

CWE-79CWE-434

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Initial Access Execution Stealth

T1190Exploit Public-Facing Application T1574.010Services File Permissions Weakness

References

Potentially impacted assets

See if this affects your attack surface

Latest trending attack

Criticaltoday

Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)

This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it. Why a second control CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution. Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library. The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support. What this control checks Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service. How to read the result Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside. This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification. Two situations are possible. When the decoding is done by your own application or reverse proxy, identify the component and update it. If an update is not possible right away, reject requests with "Content-Encoding: br" at the reverse proxy or WAF. When the asset is hosted on a managed platform or behind a CDN (for example Platform.sh, Upsun or Fastly), the decoding may be done by the provider's edge router, in front of your application. You cannot patch it yourself, but this router handles all the traffic of your site. Ask your provider to confirm that its edge components are patched against CVE-2026-111497. Assets hosted on a managed platform or behind a CDN carry the tag "paas: platform.sh" or "cdn: fastly" in the asset view: for these assets, the Brotli decoding is done by the provider's edge router, in front of your application, and only the provider can patch it. Affected and fixed versions Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution. Recommendations Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library. Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli. Contact your edge provider about the status of the pathing (Fastly / Plateform.sh) Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.