FileBrowser Quantum: Password-Protected Share Bypass via /public/api/share/info

Exploitation

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

CVSS 4.0

7.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-30933: 0.58% estimated exploitation activity in the next 30 days; percentile 47.65 (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 remediation for CVE-2026-27611 appears incomplete. Password protected shares still disclose tokenized downloadURL via /public/api/share/info in docker image gtstef/filebrowser:1.3.1-webdav-2. Details The issue stems from two flaws: 1. Tokenized download URLs are written into the persistent share model 2. The public endpoint: Since Token is set for password-protected shares, and getShareURL(..., true, token) embeds it as a query parameter, the public API discloses a valid bearer download capability. The previous patch removed token generation in one handler but did not address the persisted DownloadURL values/Public reflection of existing DownloadURL PoC 1. Create a password protected share as an authenticated user 2. Copy the public share URL (the clipboard WITHOUT an arrow) http://yourdomain/public/share/yoursharedhash Example: http://yourdomain/public/share/2EBGbXgXg5dpw-nK0RG6vw 3. Query the public share endpoint via curl request: curl…

Published by the source

9 Mar 2026, 19:48 UTC

Last modified by the source

27 Apr 2026, 14:57 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-525j-95gf-766f

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# Patch Next advisory brief: CVE-2026-30933

Advisory: FileBrowser Quantum: Password-Protected Share Bypass via /public/api/share/info
IDs: CVE-2026-30933, GHSA-525j-95gf-766f
Record: https://patchnext.com/advisories/cve-2026-30933 (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: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gtsteffaniak/filebrowser/backend 0.0.0-20260307130210-09713b32a5f6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gtsteffaniak/filebrowser/backend: affected < 0.0.0-20260307130210-09713b32a5f6; fixed in 0.0.0-20260307130210-09713b32a5f6

## Suggested inspection (read-only)
- Go github.com/gtsteffaniak/filebrowser/backend: 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/gtsteffaniak/filebrowser/backend.
- 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-525j-95gf-766f (GitHub-reviewed advisory GHSA-525j-95gf-766f lists affected ranges: Go github.com/gtsteffaniak/filebrowser/backend >=0 <0.0.0-20260307130210-09713b32a5f6)

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