CVE-2026-49836

Path traversal, arbitrary file write/read via smart object names.

• CVSS 4.6
• 22
• Input Validation and Sanitization
• Remote

psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to version 1.17.1, `SmartObject.save()` writes an embedded smart object to a path taken verbatim from the PSD file. Because that name is attacker-controlled and unsanitised, a tool that extracts embedded objects from an untrusted `.psd` can be made to write attacker-chosen bytes to an attacker-chosen path (absolute or `../`-traversing), outside its intended output directory. A secondary issue in `SmartObject.open()` for external-kind smart objects allows the attacker-controlled `fullPath` descriptor to be used as an arbitrary file read path, enabling exfiltration of the read content to the controlled write destination. Both issues are fixed in v1.17.1.

CVE

CVE-2026-49836

CWE

22

CVSS base score

4.6

Published

2026-09-10

OWASP

A08 Software and Data Integrity Failures

Orthogonal defect classification

Interface

Code defect classification

Missing Check

Category

Input Validation and Sanitization

Subcategory

Path Traversal

Accessibility scope

Remote

Impact

Unauthorized Access

Affected component

psd-tools

Fixed by upgrading

Yes

Solution

Upgrade psd-tools to version 1.17.1 or later.

import os
from psd_tools import PSDImage

def extract_smart_objects(psd_path: str, out_dir: str) -> None:
    """Extract embedded smart objects from a PSD file."""
    psd = PSDImage.open(psd_path)
    for layer in psd:
        if hasattr(layer, 'smart_object') and layer.smart_object:
            obj = layer.smart_object
            # VULNERABLE: writes to attacker‑controlled path from PSD metadata
            obj.save(os.path.join(out_dir, obj.name))

import os
from psd_tools import PSDImage

def extract_smart_objects(psd_path: str, out_dir: str) -> None:
    """Extract embedded smart objects from a PSD file."""
    psd = PSDImage.open(psd_path)
    for layer in psd:
        if hasattr(layer, 'smart_object') and layer.smart_object:
            obj = layer.smart_object
            # FIX: sanitize filename to prevent path traversal
            safe_name = os.path.basename(obj.name)
            obj.save(os.path.join(out_dir, safe_name))

__VAITP_MODEL_REFUSED__

@misc{vaitp:cve202649836,
  title        = {{Path traversal, arbitrary file write/read via smart object names.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-49836},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-49836/}}
}