Squid 5.x < 7.7 Stack-based Buffer Overflow (SQUID-2026:7)

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

include('compat.inc');

if (description)
{
  script_id(377052);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/06");

  script_cve_id("CVE-2026-104786");
  script_xref(name:"IAVB", value:"2026-B-0322");

  script_name(english:"Squid 5.x < 7.7 Stack-based Buffer Overflow (SQUID-2026:7)");

  script_set_attribute(attribute:"synopsis", value:
"The remote proxy server is affected by a stack-based buffer overflow vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Squid on the remote host is 5.x, 6.x or 7.x prior to 7.7. It is, therefore, affected by a stack-based
buffer overflow vulnerability:

  - Due to an Improper Input Validation bug, Squid is vulnerable to a stack-based buffer overflow attack against HTTP
    authentication. This problem allows a trusted client to perform an out-of-bounds write when Squid is configured to
    authenticate with a peer server using client provided Basic authentication credentials. This attack is limited to
    Squid deployments passing client supplied Basic authentication credentials to a cache_peer. (CVE-2026-104786)

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/squid-cache/squid/security/advisories/GHSA-j9pf-q9f6-v44c
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?63d1ba32");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Squid version 7.7 or later, or apply the patch referenced in the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-104786");
  script_cwe_id(20, 121);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/11/06");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:squid-cache:squid");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Firewalls");

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

  script_dependencies("squid_version.nasl");
  script_require_keys("installed_sw/Squid", "Settings/ParanoidReport");
  script_require_ports("Services/http_proxy", 3128, 8080);

  exit(0);
}

include('vdf.inc');

if (report_paranoia < 2)
  audit(AUDIT_PARANOID);

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'Squid', 'type': 'app'},
      'check_algorithm': 'default',
      'potential_vulnerability': {
        'low_fidelity': {'context': 'unreliable remote detection'}
      },
      'requires': [
        {'scope': 'target', 'match': {'paranoia': true}}
      ],
      'constraints': [
        {'min_version': '5.0', 'fixed_version': '7.7'}
      ]
    }
  ]
};

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