Linux Distros Unpatched Vulnerability : CVE-2025-68156

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

include('compat.inc');

if (description)
{
  script_id(278966);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/12/22");

  script_cve_id("CVE-2025-68156");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2025-68156");

  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.

  - Expr is an expression language and expression evaluation for Go. Prior to version 1.17.7, several builtin
    functions in Expr, including `flatten`, `min`, `max`, `mean`, and `median`, perform recursive traversal
    over user-provided data structures without enforcing a maximum recursion depth. If the evaluation
    environment contains deeply nested or cyclic data structures, these functions may recurse indefinitely
    until exceed the Go runtime stack limit. This results in a stack overflow panic, causing the host
    application to crash. While exploitability depends on whether an attacker can influence or inject cyclic
    or pathologically deep data into the evaluation environment, this behavior represents a denial-of-service
    (DoS) risk and affects overall library robustness. Instead of returning a recoverable evaluation error,
    the process may terminate unexpectedly. In affected versions, evaluation of expressions that invoke
    certain builtin functions on untrusted or insufficiently validated data structures can lead to a process-
    level crash due to stack exhaustion. This issue is most relevant in scenarios where Expr is used to
    evaluate expressions against externally supplied or dynamically constructed environments; cyclic
    references (directly or indirectly) can be introduced into arrays, maps, or structs; and there are no
    application-level safeguards preventing deeply nested input data. In typical use cases with controlled,
    acyclic data, the issue may not manifest. However, when present, the resulting panic can be used to
    reliably crash the application, constituting a denial of service. The issue has been fixed in the v1.17.7
    versions of Expr. The patch introduces a maximum recursion depth limit for affected builtin functions.
    When this limit is exceeded, evaluation aborts gracefully and returns a descriptive error instead of
    panicking. Additionally, the maximum depth can be customized by users via `builtin.MaxDepth`, allowing
    applications with legitimate deep structures to raise the limit in a controlled manner. Users are strongly
    encouraged to upgrade to the patched release, which includes both the recursion guard and comprehensive
    test coverage to prevent regressions. For users who cannot immediately upgrade, some mitigations are
    recommended. Ensure that evaluation environments cannot contain cyclic references, validate or sanitize
    externally supplied data structures before passing them to Expr, and/or wrap expression evaluation with
    panic recovery to prevent a full process crash (as a last-resort defensive measure). These workarounds
    reduce risk but do not fully eliminate the issue without the patch. (CVE-2025-68156)

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-2025-68156");
  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:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/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:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-68156");

  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:"2025/12/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/12/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-github-antonmedv-expr");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14");

  exit(0);
}

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-github-antonmedv-expr-dev"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "golang-github-antonmedv-expr-dev"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "golang-github-antonmedv-expr-dev"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "golang-github-antonmedv-expr-dev"}
        ]
      }
    ]
  }
};

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');
}