Linux Distros Unpatched Vulnerability : CVE-2026-1757

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

include('compat.inc');

if (description)
{
  script_id(297549);
  script_version("1.10");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/21");

  script_cve_id("CVE-2026-1757");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-1757");

  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 flaw was identified in the interactive shell of the xmllint utility, part of the libxml2 project, where
    memory allocated for user input is not properly released under certain conditions. When a user submits
    input consisting only of whitespace, the program skips command execution but fails to free the allocated
    buffer. Repeating this action causes memory to continuously accumulate. Over time, this can exhaust system
    memory and terminate the xmllint process, creating a denial-of-service condition on the local system.
    (CVE-2026-1757)

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-2026-1757");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-1757");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-1757");
  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: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:L/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-2026-1757");

  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:"2026/02/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/02/02");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");
  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:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  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:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2-python");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2-static");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:python3-libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libxml2-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libxml2-python");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libxml2-static");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-libxml2");
  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-7", "Host/OS/CentOS Linux-8", "Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-7", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9", "Host/OS/Ubuntu Linux-25.10");

  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": "libxml2"},
          {"reference": "libxml2-dev"},
          {"reference": "libxml2-doc"},
          {"reference": "libxml2-utils"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-dev"},
          {"reference": "libxml2-doc"},
          {"reference": "libxml2-utils"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-dev"},
          {"reference": "libxml2-doc"},
          {"reference": "libxml2-utils"},
          {"reference": "python3-libxml2"},
          {"reference": "python3-libxml2-dbg"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "libxml2-16"},
          {"reference": "libxml2-dev"},
          {"reference": "libxml2-doc"},
          {"reference": "libxml2-utils"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "libxml2-static"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "libxml2-python"},
          {"reference": "libxml2-static"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "libxml2-python"},
          {"reference": "libxml2-static"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "libxml2"},
          {"reference": "libxml2-devel"},
          {"reference": "python3-libxml2"}
        ]
      }
    ]
  }
};

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');
}