LangChain < 1.3.9 Path Traversal (CVE-2026-55443)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(322754);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/29");

  script_cve_id("CVE-2026-55443");

  script_name(english:"LangChain < 1.3.9 Path Traversal (CVE-2026-55443)");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is affected by a path traversal vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of LangChain installed on the remote host is prior to 1.3.9. It is, therefore,
affected by a path traversal vulnerability:

  - Several LangChain components that resolve filesystem paths or expand search patterns do not
    consistently confine the resolved path to the intended root directory. Affected behaviors
    include a file-search agent middleware that validates a starting directory but not the search
    pattern or resolved target of matched files, prompt and chain/agent-configuration loaders that
    accept path fields and resolve them without confining the result to a trusted base, and
    path-prefix authorization checks that compare by string prefix without a path-segment boundary.
    When these components receive path values influenced by an untrusted source, the result can be
    disclosure of files outside the intended boundary. (CVE-2026-55443)

Note that Nessus has not tested for this issue but has instead relied only on the application's
self-reported version number.");
  # https://github.com/langchain-ai/langchain/security/advisories/GHSA-gr75-jv2w-4656
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7695fc88");
  script_set_attribute(attribute:"solution", value:
"Upgrade to LangChain version 1.3.9 or later.");
  script_set_attribute(attribute:"agent", value:"all");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-55443");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:langchain-ai:langchain");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Artificial Intelligence");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("python_langchain_detect.nbin");
  script_require_keys("installed_sw/LangChain");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'LangChain', 'type': 'app'},
      'check_algorithm': 'default',
      'constraints': [
        {'fixed_version': '1.3.9'}
      ]
    }
  ]
};

var result = vdf::check_and_report(vuln_data:vuln_data, severity:SECURITY_WARNING);
vdf::handle_check_and_report_errors(vdf_result:result);