Rclone 1.75.0 S3 Multipart Declared-Length Memory Exhaustion (CVE-2026-88045)

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

include('compat.inc');

if (description)
{
  script_id(346830);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/18");

  script_cve_id("CVE-2026-88045");
  script_xref(name:"IAVB", value:"2026-B-0256");

  script_name(english:"Rclone 1.75.0 S3 Multipart Declared-Length Memory Exhaustion (CVE-2026-88045)");

  script_set_attribute(attribute:"synopsis", value:
"An application installed on the remote host is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Rclone installed on the remote host is 1.75.0. It is, therefore,
affected by a denial of service vulnerability:

  - In streamed multipart mode, rclone serve s3 passes the request's declared part length to
    multipart.NewRW().Reserve(contentLength) before reading any part data, which immediately
    obtains enough 1 MiB pool pages for the entire declared length. A network client can therefore
    cause the server to reserve memory proportional to an unverified Content-Length or
    X-Amz-Decoded-Content-Length header without transmitting the corresponding body, and
    --multipart-streaming-buffer-limit does not cap the allocation for the current expected part.
    A sufficiently large declared length, or concurrent requests, can exhaust process or host
    memory or permanently block request goroutines, resulting in loss of S3 service availability.
    (CVE-2026-88045)

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/rclone/rclone/security/advisories/GHSA-2p48-j3qc-rx9f
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6e2a4ea8");
  script_set_attribute(attribute:"see_also", value:"https://github.com/rclone/rclone/releases/tag/v1.75.1");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Rclone version 1.75.1 or later.");
  script_set_attribute(attribute:"agent", value:"all");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-88045");

  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:"2026/09/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:rclone:rclone");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

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

  script_dependencies("rclone_win_installed.nbin", "rclone_macos_installed.nbin", "rclone_nix_installed.nbin");
  script_require_keys("installed_sw/rclone");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'rclone', 'type': 'app'},
      'check_algorithm': 'default',
      'constraints': [
        {'min_version': '1.75.0', 'fixed_version': '1.75.1'}
      ]
    }
  ]
};

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