File Browser vulnerable to Stored Cross-site Scripting via text/template branding injection

Exploitation

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

CVSS

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

EPSS

• CVE-2026-34530: 0.37% estimated exploitation activity in the next 30 days; percentile 30.95 (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 SPA index page in File Browser is vulnerable to Stored Cross-site Scripting (XSS) via admin-controlled branding fields. An admin who sets branding.name to a malicious payload injects persistent JavaScript that executes for ALL visitors, including unauthenticated users. <br/ Details http/static.go renders the SPA index.html using Go's text/template (NOT html/template) with custom delimiters [{[ and ]}]. Branding fields are inserted directly into HTML without any escaping: The frontend template (frontend/public/index.html) embeds these fields directly: Since text/template performs NO HTML escaping (unlike html/template), setting branding.name to </title<scriptalert(1)</script breaks out of the <title tag and injects arbitrary script into every page load. Additionally, when ReCaptcha is enabled, the ReCaptchaHost field is used as: This allows loading arbitrary JavaScript from an admin-chosen origin. No Content-Security-Policy header is set on the SPA entry point, so there is…

Published by the source

31 Mar 2026, 23:45 UTC

Last modified by the source

6 Apr 2026, 17:13 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xfqj-3vmx-63wv

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# Patch Next advisory brief: CVE-2026-34530

Advisory: File Browser vulnerable to Stored Cross-site Scripting via text/template branding injection
IDs: CVE-2026-34530, GHSA-xfqj-3vmx-63wv
Record: https://patchnext.com/advisories/cve-2026-34530 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/filebrowser/filebrowser/v2 2.62.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/filebrowser/filebrowser/v2: affected <= 2.62.1; fixed in 2.62.2

## Suggested inspection (read-only)
- Go github.com/filebrowser/filebrowser/v2: check the installed version with your package manager.

## 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 github.com/filebrowser/filebrowser/v2.
- 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-xfqj-3vmx-63wv (GitHub-reviewed advisory GHSA-xfqj-3vmx-63wv lists affected ranges: Go github.com/filebrowser/filebrowser/v2 >=0 <=2.62.1)

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