CVE-2026-10595

Unauthenticated path traversal in lollms < 3.0 allows arbitrary file read.

• CVSS 7.5
• 23
• Input Validation and Sanitization
• Remote

A path traversal vulnerability exists in parisneo/lollms version 2.1.0, specifically in the SPA catch-all route implemented in `backend/routers/ui.py`. The vulnerability arises from the improper handling of user-controlled path input, which is directly joined into a filesystem path without sanitization or containment checks. URL-encoded dot-dot sequences (`%2e%2e`) bypass Starlette's built-in path normalization and are resolved by Python's `pathlib`, allowing an unauthenticated attacker to read arbitrary files on the server. This issue has been resolved in version 3.

CVE

CVE-2026-10595

CWE

23

CVSS base score

7.5

Published

2026-08-09

OWASP

A01 Broken Access Control

Orthogonal defect classification

Checking

Code defect classification

Missing Check

Category

Input Validation and Sanitization

Subcategory

Path Traversal

Accessibility scope

Remote

Impact

Information Disclosure

Affected component

parisneo/lol

Fixed by upgrading

Yes

Solution

Upgrade parisneo/lollms to version 3.0 or later.

import pathlib
from fastapi import APIRouter, Request
from fastapi.responses import FileResponse

router = APIRouter()

# A placeholder for a configuration object holding paths
class LollmsPaths:
    ui_path = pathlib.Path("front_end/dist")

lollms_paths = LollmsPaths()

@router.get("/{path:path}")
async def get_spa(request: Request, path: str):
    """
    Serves Single Page Application files.
    """
    if not path:
        path = "index.html"
        
    # VULNERABLE: The user-provided path is directly joined without sanitization, allowing path traversal.
    static_file_path = lollms_paths.ui_path / path

    if static_file_path.is_file():
        return FileResponse(static_file_path)
    else:
        # Fallback to index.html for SPA routing
        index_path = lollms_paths.ui_path / "index.html"
        return FileResponse(index_path)

import pathlib
import os
from fastapi import APIRouter, Request, HTTPException
from fastapi.responses import FileResponse

router = APIRouter()

# A placeholder for a configuration object holding paths
class LollmsPaths:
    ui_path = pathlib.Path("front_end/dist")

lollms_paths = LollmsPaths()

@router.get("/{path:path}")
async def get_spa(request: Request, path: str):
    """
    Serves Single Page Application files.
    """
    if not path:
        path = "index.html"
        
    base_dir = lollms_paths.ui_path.resolve()
    # FIX: The requested path is resolved and checked to be within the base directory.
    requested_path = (base_dir / path).resolve()

    if os.path.commonpath([base_dir, requested_path]) != str(base_dir):
        raise HTTPException(status_code=404, detail="Not Found")

    if requested_path.is_file():
        return FileResponse(requested_path)
    else:
        # Fallback to index.html for SPA routing
        index_path = lollms_paths.ui_path / "index.html"
        return FileResponse(index_path)

%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/etc/passwd

@misc{vaitp:cve202610595,
  title        = {{Unauthenticated path traversal in lollms < 3.0 allows arbitrary file read.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-10595},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-10595/}}
}