Linux Distros Unpatched Vulnerability : CVE-2026-48855

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

include('compat.inc');

if (description)
{
  script_id(320494);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/11");

  script_cve_id("CVE-2026-48855");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-48855");

  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.

  - Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Erlang OTP ssh (ssh_sftpd
    module) allows File Discovery. The SSH_FXP_READLINK handler in ssh_sftpd sends the raw result of
    file:read_link/2 to the client without calling chroot_filename/2 to strip the backend root prefix. An
    authenticated SFTP client can create a symlink inside the chroot pointing to /; ssh_sftpd resolves the
    target to the absolute backend root and stores it on disk. Reading the symlink back via SSH_FXP_READLINK
    returns that absolute path, for example /data/sftp, instead of the chrooted value /. The information
    disclosed is the absolute filesystem path of the SFTP root directory and of any symlink targets within it.
    No file contents, credentials, or access to paths outside the root directory are obtainable through this
    issue alone. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue
    affects OTP from OTP 17.0 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to ssh from 3.0.1 before
    6.0.1, 5.5.2.1 and 5.2.11.8. (CVE-2026-48855)

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-2026-48855");
  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:P/I:P/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:H/I:H/A:H");
  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:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-48855");

  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:"2026/06/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/11");

  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:erlang");
  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/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-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "erlang"},
          {"reference": "erlang-asn1"},
          {"reference": "erlang-base"},
          {"reference": "erlang-common-test"},
          {"reference": "erlang-crypto"},
          {"reference": "erlang-debugger"},
          {"reference": "erlang-dev"},
          {"reference": "erlang-dialyzer"},
          {"reference": "erlang-diameter"},
          {"reference": "erlang-doc"},
          {"reference": "erlang-edoc"},
          {"reference": "erlang-eldap"},
          {"reference": "erlang-erl-docgen"},
          {"reference": "erlang-et"},
          {"reference": "erlang-eunit"},
          {"reference": "erlang-examples"},
          {"reference": "erlang-ftp"},
          {"reference": "erlang-inets"},
          {"reference": "erlang-jinterface"},
          {"reference": "erlang-manpages"},
          {"reference": "erlang-megaco"},
          {"reference": "erlang-mnesia"},
          {"reference": "erlang-mode"},
          {"reference": "erlang-nox"},
          {"reference": "erlang-observer"},
          {"reference": "erlang-odbc"},
          {"reference": "erlang-os-mon"},
          {"reference": "erlang-parsetools"},
          {"reference": "erlang-public-key"},
          {"reference": "erlang-reltool"},
          {"reference": "erlang-runtime-tools"},
          {"reference": "erlang-snmp"},
          {"reference": "erlang-src"},
          {"reference": "erlang-ssh"},
          {"reference": "erlang-ssl"},
          {"reference": "erlang-syntax-tools"},
          {"reference": "erlang-tftp"},
          {"reference": "erlang-tools"},
          {"reference": "erlang-wx"},
          {"reference": "erlang-x11"},
          {"reference": "erlang-xmerl"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "erlang"},
          {"reference": "erlang-asn1"},
          {"reference": "erlang-base"},
          {"reference": "erlang-base-hipe"},
          {"reference": "erlang-common-test"},
          {"reference": "erlang-crypto"},
          {"reference": "erlang-debugger"},
          {"reference": "erlang-dev"},
          {"reference": "erlang-dialyzer"},
          {"reference": "erlang-diameter"},
          {"reference": "erlang-doc"},
          {"reference": "erlang-edoc"},
          {"reference": "erlang-eldap"},
          {"reference": "erlang-erl-docgen"},
          {"reference": "erlang-et"},
          {"reference": "erlang-eunit"},
          {"reference": "erlang-examples"},
          {"reference": "erlang-ftp"},
          {"reference": "erlang-inets"},
          {"reference": "erlang-jinterface"},
          {"reference": "erlang-manpages"},
          {"reference": "erlang-megaco"},
          {"reference": "erlang-mnesia"},
          {"reference": "erlang-mode"},
          {"reference": "erlang-nox"},
          {"reference": "erlang-observer"},
          {"reference": "erlang-odbc"},
          {"reference": "erlang-os-mon"},
          {"reference": "erlang-parsetools"},
          {"reference": "erlang-public-key"},
          {"reference": "erlang-reltool"},
          {"reference": "erlang-runtime-tools"},
          {"reference": "erlang-snmp"},
          {"reference": "erlang-src"},
          {"reference": "erlang-ssh"},
          {"reference": "erlang-ssl"},
          {"reference": "erlang-syntax-tools"},
          {"reference": "erlang-tftp"},
          {"reference": "erlang-tools"},
          {"reference": "erlang-wx"},
          {"reference": "erlang-x11"},
          {"reference": "erlang-xmerl"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "erlang"},
          {"reference": "erlang-asn1"},
          {"reference": "erlang-base"},
          {"reference": "erlang-common-test"},
          {"reference": "erlang-crypto"},
          {"reference": "erlang-debugger"},
          {"reference": "erlang-dev"},
          {"reference": "erlang-dialyzer"},
          {"reference": "erlang-diameter"},
          {"reference": "erlang-doc"},
          {"reference": "erlang-edoc"},
          {"reference": "erlang-eldap"},
          {"reference": "erlang-et"},
          {"reference": "erlang-eunit"},
          {"reference": "erlang-examples"},
          {"reference": "erlang-ftp"},
          {"reference": "erlang-inets"},
          {"reference": "erlang-jinterface"},
          {"reference": "erlang-megaco"},
          {"reference": "erlang-mnesia"},
          {"reference": "erlang-mode"},
          {"reference": "erlang-nox"},
          {"reference": "erlang-observer"},
          {"reference": "erlang-odbc"},
          {"reference": "erlang-os-mon"},
          {"reference": "erlang-parsetools"},
          {"reference": "erlang-public-key"},
          {"reference": "erlang-reltool"},
          {"reference": "erlang-runtime-tools"},
          {"reference": "erlang-snmp"},
          {"reference": "erlang-src"},
          {"reference": "erlang-ssh"},
          {"reference": "erlang-ssl"},
          {"reference": "erlang-syntax-tools"},
          {"reference": "erlang-tftp"},
          {"reference": "erlang-tools"},
          {"reference": "erlang-wx"},
          {"reference": "erlang-x11"},
          {"reference": "erlang-xmerl"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "erlang"},
          {"reference": "erlang-asn1"},
          {"reference": "erlang-base"},
          {"reference": "erlang-common-test"},
          {"reference": "erlang-crypto"},
          {"reference": "erlang-debugger"},
          {"reference": "erlang-dev"},
          {"reference": "erlang-dialyzer"},
          {"reference": "erlang-diameter"},
          {"reference": "erlang-doc"},
          {"reference": "erlang-edoc"},
          {"reference": "erlang-eldap"},
          {"reference": "erlang-et"},
          {"reference": "erlang-eunit"},
          {"reference": "erlang-examples"},
          {"reference": "erlang-ftp"},
          {"reference": "erlang-inets"},
          {"reference": "erlang-jinterface"},
          {"reference": "erlang-megaco"},
          {"reference": "erlang-mnesia"},
          {"reference": "erlang-mode"},
          {"reference": "erlang-nox"},
          {"reference": "erlang-observer"},
          {"reference": "erlang-odbc"},
          {"reference": "erlang-os-mon"},
          {"reference": "erlang-parsetools"},
          {"reference": "erlang-public-key"},
          {"reference": "erlang-reltool"},
          {"reference": "erlang-runtime-tools"},
          {"reference": "erlang-snmp"},
          {"reference": "erlang-src"},
          {"reference": "erlang-ssh"},
          {"reference": "erlang-ssl"},
          {"reference": "erlang-syntax-tools"},
          {"reference": "erlang-tftp"},
          {"reference": "erlang-tools"},
          {"reference": "erlang-wx"},
          {"reference": "erlang-x11"},
          {"reference": "erlang-xmerl"}
        ]
      }
    ]
  }
};

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');
}