How severe is CVE-2026-28492?

No CVSS score has been assigned to CVE-2026-28492 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-28492?

CVE-2026-28492 affects the following packages: github.com/filebrowser/filebrowser/v2 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-28492?

Update github.com/filebrowser/filebrowser/v2 to 2.61.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28492 is resolved across your whole dependency graph.

How do I detect CVE-2026-28492 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/filebrowser/filebrowser/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-28492 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2026-28492 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28492 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 CVE-2026-28492?

CVE-2026-28492 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th 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 CVE-2026-28492?

CVE-2026-28492 is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-28492 published, and has it been updated?

CVE-2026-28492 was published on March 5, 2026 and was last updated on October 28, 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

Not in CISA KEV

CVE-2026-28492 — filebrowser

Fix: filebrowser/filebrowser@31194fb

CVE-2026-28492 is a Information Exposure vulnerability in github.com/filebrowser/filebrowser/v2. A fix is available for github.com/filebrowser/filebrowser/v2 — see the affected versions and patch details below.

File Browser: Path Traversal in Public Share Links Exposes Files Outside Shared Directory

Also known asGHSA-mr74-928f-rw69GO-2026-4585

Published

Mar 5, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-28492.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs31th percentile — riskier than 31% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/filebrowser/filebrowser/v2

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

When a user creates a public share link for a directory, the withHashFile middleware in http/public.go (line 59) uses filepath.Dir(link.Path) to compute the BasePathFs root. This sets the filesystem root to the parent directory instead of the shared directory itself, allowing anyone with the share link to browse and download files from all sibling directories.

Details

In http/public.go lines 52-64, the withHashFile function handles public share link requests:

basePath := link.Path    // e.g. "/documents/shared"
filePath := ""

if file.IsDir {
    basePath = filepath.Dir(basePath)  // BUG: becomes "/documents" (parent!)
    filePath = ifPath
}

d.user.Fs = afero.NewBasePathFs(d.user.Fs, basePath)

When a directory at /documents/shared is shared, filepath.Dir("/documents/shared") evaluates to "/documents". The BasePathFs is then rooted at the parent directory /documents/, giving the share link access to everything under /documents/ - not just the intended /documents/shared/.

This affects both publicShareHandler (directory listing via /api/public/share/{hash}) and publicDlHandler (file download via /api/public/dl/{hash}/path).

PoC

Set up filebrowser with a user whose scope contains:
- /documents/shared/public-file.txt (intended to be shared)
- /documents/secrets/passwords.txt (NOT intended to be shared)
- /documents/private/financial.csv (NOT intended to be shared)
Create a public share link for the directory /documents/shared (via POST /api/share/documents/shared)
Access the share link: GET /api/public/share/{hash}
- Expected: Lists only contents of /documents/shared/
- Actual: Lists contents of /documents/ (parent), revealing secrets/, private/, and shared/ directories
Download sibling files: GET /api/public/dl/{hash}/secrets/passwords.txt
- Expected: 404 or 403 (file outside share scope)
- Actual: 200 with file contents (sibling file downloaded successfully) Standalone Go test reproducing the exact vulnerable code path with afero.NewBasePathFs:

func TestShareScopeEscape(t *testing.T) {
    baseFs := afero.NewMemMapFs()
    afero.WriteFile(baseFs, "/documents/shared/public.txt", []byte("public"), 0644)
    afero.WriteFile(baseFs, "/documents/secrets/passwords.txt", []byte("admin:hunter2"), 0644)

    linkPath := "/documents/shared"
    basePath := filepath.Dir(linkPath) // BUG: "/documents"
    scopedFs := afero.NewBasePathFs(baseFs, basePath)

    // Sibling file is accessible through the share:
    f, err := scopedFs.Open("/secrets/passwords.txt")
    // err is nil - file accessible! Content: "admin:hunter2"
}

This test passes, confirming the vulnerability.

Impact

Unauthenticated information disclosure (CWE-200, CWE-706). Anyone with a public share link for a directory can:

Browse all sibling directories and files of the shared directory
- Download any file within the parent directory scope
- This works without authentication (public shares) or after providing the share password (password-protected shares) All filebrowser v2.x installations that use directory sharing are affected.

Recommended Fix

Remove the filepath.Dir() call and use link.Path directly as the BasePathFs root:

if file.IsDir {
    // Don't change basePath - keep it as link.Path
    filePath = ifPath
}
d.user.Fs = afero.NewBasePathFs(d.user.Fs, basePath)

Affected commit: e3d00d591b567a8bfe3b02e42ba586859002c77d (latest) File: http/public.go, line 59

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/filebrowser/filebrowser/v2`	all versions	2.61.0`go get github.com/filebrowser/filebrowser/v2@v2.61.0`

Affected Products

1 product · 1 configurations

Application

filebrowserfilebrowser

≥ 2.0.0 && < 2.61.0

range

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/filebrowser/filebrowser/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/filebrowser/filebrowser/v2 to 2.61.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28492 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

### Summary When a user creates a public share link for a **directory**, the `withHashFile` middleware in `http/public.go` (line 59) uses `filepath.Dir(link.Path)` to compute the `BasePathFs` root. This sets the filesystem root to the **parent directory** instead of the shared directory itself, allowing anyone with the share link to browse and download files from all sibling directories. ### Details In `http/public.go` lines 52-64, the `withHashFile` function handles public share link requests: ```go basePath := link.Path // e.g. "/documents/shared" filePath := "" if file.IsDir { bas

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