Linux Distros Unpatched Vulnerability : CVE-2026-34182

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

include('compat.inc');

if (description)
{
  script_id(320341);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/10");

  script_cve_id("CVE-2026-34182");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-34182");

  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.

  - Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input
    validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various
    potential compromises. Impact Summary: Attackers making use of these vulnerabilities may achieve key-
    equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message.
    In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified
    as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the
    message. An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim
    can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still
    unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB
    (Output Feedback Mode, an unauthenticated keystream mode) and with an attacker-chosen IV and ciphertext.
    The victim initializes AES-256-OFB under the real CEK, never consults the MAC field, and CMS_decrypt()
    returns success. If the application under attack responds to the attacker with any indicator showing
    success or failure of the decryption effort, it is possible for the attacker to use this as an oracle to
    obtain key equivalent functionality for the CEK used for the chosen recipient of the message. In another
    use case, an attacker can reduce the tag length of the chosen AEAD cipher for a given AuthEnvelopedData
    container to be a single byte long, allowing an attacker to brute force CMS decryption, producing an
    integrity bypass for applications that trust CMS_decrypt() to reject modified content. The FIPS modules
    are not affected by this issue. (CVE-2026-34182)

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-2026-34182");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-34182");
  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:M/Au:N/C:P/I:P/A:N");
  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:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-34182");

  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:"2026/06/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:edk2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:nodejs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssl");
  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-14", "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/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": "libcrypto1.1-udeb"},
          {"reference": "libssl-dev"},
          {"reference": "libssl-doc"},
          {"reference": "libssl1.1"},
          {"reference": "libssl1.1-udeb"},
          {"reference": "openssl"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "libcrypto3-udeb"},
          {"reference": "libssl-dev"},
          {"reference": "libssl-doc"},
          {"reference": "libssl3-udeb"},
          {"reference": "libssl3t64"},
          {"reference": "openssl"},
          {"reference": "openssl-provider-fips"},
          {"reference": "openssl-provider-legacy"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "nodejs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "efi-shell-aa64"},
          {"reference": "efi-shell-arm"},
          {"reference": "efi-shell-ia32"},
          {"reference": "efi-shell-riscv64"},
          {"reference": "efi-shell-x64"},
          {"reference": "ovmf"},
          {"reference": "ovmf-ia32"},
          {"reference": "qemu-efi-aarch64"},
          {"reference": "qemu-efi-arm"},
          {"reference": "qemu-efi-riscv64"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "efi-shell-aa64"},
          {"reference": "efi-shell-arm"},
          {"reference": "efi-shell-ia32"},
          {"reference": "efi-shell-loongarch64"},
          {"reference": "efi-shell-riscv64"},
          {"reference": "efi-shell-x64"},
          {"reference": "ovmf"},
          {"reference": "ovmf-ia32"},
          {"reference": "ovmf-inteltdx"},
          {"reference": "qemu-efi-aarch64"},
          {"reference": "qemu-efi-arm"},
          {"reference": "qemu-efi-loongarch64"},
          {"reference": "qemu-efi-riscv64"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "efi-shell-aa64"},
          {"reference": "efi-shell-loongarch64"},
          {"reference": "efi-shell-riscv64"},
          {"reference": "efi-shell-x64"},
          {"reference": "ovmf"},
          {"reference": "ovmf-amdsev"},
          {"reference": "ovmf-generic"},
          {"reference": "ovmf-inteltdx"},
          {"reference": "ovmf-legacy"},
          {"reference": "qemu-efi-aarch64"},
          {"reference": "qemu-efi-loongarch64"},
          {"reference": "qemu-efi-riscv64"}
        ]
      }
    ]
  }
};

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');
}