Linux Distros Unpatched Vulnerability : CVE-2026-54411

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

include('compat.inc');

if (description)
{
  script_id(321158);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/20");

  script_cve_id("CVE-2026-54411");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-54411");

  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.

  - Linux-PAM through 1.7.2 contains an observable timing discrepancy (CWE-208) in the pam_userdb module's
    plaintext-password comparison path in modules/pam_userdb/pam_userdb.c that allows a local or network-
    adjacent attacker able to repeatedly drive authentication through a calling service to recover the
    plaintext password of a target account by measuring response-timing differences. The comparison uses
    strncmp() (or strncasecmp() when PAM_ICASE_ARG is set) preceded by a length-equality check, so the time to
    reject a candidate depends on the index of the first differing byte and on whether the candidate's length
    matches the stored password, leaking the password length and individual prefix bytes. The vulnerable path
    is reached when the administrator configures pam_userdb with crypt=none, with an unrecognized crypt
    method, or without a crypt= argument, causing the module to store and compare credentials in plaintext.
    (CVE-2026-54411)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-54411");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-54411");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-54411");
  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:L/AC:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_supplemental", value:"CVSS:4.0/AU:N/V:D");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-54411");

  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:"2026/06/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
  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:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:pam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pam-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pam-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:pam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:pam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:pam-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:pam-docs");
  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) 2026 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/CentOS Linux-8", "Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9", "Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-25.10", "Host/OS/Ubuntu Linux-26.04");

  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/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/Debian/dpkg-l")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "libpam-cracklib"},
          {"reference": "libpam-doc"},
          {"reference": "libpam-modules"},
          {"reference": "libpam-modules-bin"},
          {"reference": "libpam-runtime"},
          {"reference": "libpam0g"},
          {"reference": "libpam0g-dev"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "pam"},
          {"reference": "pam-devel"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "pam"},
          {"reference": "pam-devel"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "pam"},
          {"reference": "pam-devel"},
          {"reference": "pam-docs"}
        ]
      }
    ]
  }
};

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_NOTE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}