Linux Distros Unpatched Vulnerability : CVE-2026-42501

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

include('compat.inc');

if (description)
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  script_id(313248);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/22");

  script_cve_id("CVE-2026-42501");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-42501");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass
    checksum database validation. This vulnerability affects any user using an untrusted module proxy
    (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions of the Go
    toolchain. When selecting a different version of the Go toolchain than the currently installed toolchain
    (due to the GOTOOLCHAIN environment variable, or a go.work or go.mod with a toolchain line), the go
    command will download and execute a toolchain provided by the module proxy. A malicious module proxy can
    bypass checksum database validation for this downloaded toolchain. Since this vulnerability affects the
    security of toolchain downloads, setting GOTOOLCHAIN to a fixed version is not sufficient. You must
    upgrade your base Go toolchain. The go tool always validates the hash of a toolchain before executing it,
    so fixed versions will refuse to execute any cached, altered versions of the toolchain. The go tool trusts
    go.sum files to contain accurate hashes of the current module's dependencies. A malicious proxy exploiting
    this vulnerability to serve an altered module will have caused an incorrect hash to be recorded in the
    go.sum. Users who have configured a non-trusted GOPROXY can determine if they have been affected by
    running rm go.sum ; go mod tidy ; go mod verify, which will revalidate all dependencies of the current
    module. The specific flaw in more detail: The go command consults the checksum database to validate
    downloaded modules, when a module is not listed in the go.sum file. It verifies that the module hash
    reported by the checksum database matches the hash of the downloaded module. If, however, the checksum
    database returns a successful response that contains no entry for the module, the go command incorrectly
    permitted validation to succeed. A module proxy may mirror or proxy the checksum database, in which case
    the go command will not connect to the checksum database directly. Checksums reported by the checksum
    database are cryptographically signed, so a malicious proxy cannot alter the reported checksum for a
    module. However, a proxy which returns an empty checksum response, or a checksum response for an unrelated
    module, could cause the go command to proceed as if a downloaded module has been validated.
    (CVE-2026-42501)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-42501");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-42501");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:S/C:C/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-42501");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/05/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/08");

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}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "golang-1.15"},
          {"reference": "golang-1.15-doc"},
          {"reference": "golang-1.15-go"},
          {"reference": "golang-1.15-src"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "golang-1.19"},
          {"reference": "golang-1.19-doc"},
          {"reference": "golang-1.19-go"},
          {"reference": "golang-1.19-src"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "golang-1.24"},
          {"reference": "golang-1.24-doc"},
          {"reference": "golang-1.24-go"},
          {"reference": "golang-1.24-src"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "golang-1.10"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "golang-1.10"},
          {"reference": "golang-1.13"},
          {"reference": "golang-1.18"},
          {"reference": "golang-1.6"},
          {"reference": "golang-1.6-doc"},
          {"reference": "golang-1.6-go"},
          {"reference": "golang-1.6-src"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "golang-1.10"},
          {"reference": "golang-1.10-doc"},
          {"reference": "golang-1.10-go"},
          {"reference": "golang-1.10-src"},
          {"reference": "golang-1.13"},
          {"reference": "golang-1.16"},
          {"reference": "golang-1.18"},
          {"reference": "golang-1.8"},
          {"reference": "golang-1.9"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "golang-1.13"},
          {"reference": "golang-1.13-doc"},
          {"reference": "golang-1.13-go"},
          {"reference": "golang-1.13-src"},
          {"reference": "golang-1.14"},
          {"reference": "golang-1.14-doc"},
          {"reference": "golang-1.14-go"},
          {"reference": "golang-1.14-src"},
          {"reference": "golang-1.16"},
          {"reference": "golang-1.18"},
          {"reference": "golang-1.20"},
          {"reference": "golang-1.21"},
          {"reference": "golang-1.22"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "golang-1.13"},
          {"reference": "golang-1.17"},
          {"reference": "golang-1.17-doc"},
          {"reference": "golang-1.17-go"},
          {"reference": "golang-1.17-src"},
          {"reference": "golang-1.18"},
          {"reference": "golang-1.18-doc"},
          {"reference": "golang-1.18-go"},
          {"reference": "golang-1.18-src"},
          {"reference": "golang-1.20"},
          {"reference": "golang-1.21"},
          {"reference": "golang-1.22"},
          {"reference": "golang-1.23"},
          {"reference": "golang-1.24"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "golang-1.21"},
          {"reference": "golang-1.22"},
          {"reference": "golang-1.22-doc"},
          {"reference": "golang-1.22-go"},
          {"reference": "golang-1.22-src"},
          {"reference": "golang-1.23"},
          {"reference": "golang-1.24"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "golang-1.23"},
          {"reference": "golang-1.24"},
          {"reference": "golang-1.24-doc"},
          {"reference": "golang-1.24-go"},
          {"reference": "golang-1.24-src"},
          {"reference": "golang-1.25"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}