Linux Distros Unpatched Vulnerability : CVE-2026-75804

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

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  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2026-75804");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-75804");

  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: OpenSSL QUIC stack does not enforce connection level flow control for streams. Remote peers
    may send more bytes as long as they fit within the stream flow control limits. Impact summary: A malicious
    remote peer may exploit the lack of connection flow control for streams to make the QUIC stack receive
    ~100MB of memory instead of 768 KiB (default flow control window size). CWE: CWE-770: Allocation of
    Resources Without Limits or Throttling Description: The local QUIC stack advertises two flow control
    limits to its remote peer: stream flow control limit and connection flow control limit. The remote peer
    must follow both limits when transmitting stream data. Whenever the local QUIC stack receives a stream
    frame, it validates that the size of the received stream frame stays within flow control limits. If either
    limit is exceeded (stream level or connection level), then the QUIC stack must close the connection with a
    flow control error. The vulnerable OpenSSL QUIC stack enforces the stream-level but not the connection-
    level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams -
    each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent
    on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the
    conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control
    limit) bytes of memory. MAX_STREAMS defaults to 100, and the limit applies to both bidirectional and
    unidirectional streams, making it 200 in total. The default flow control window for a stream is 512kB. The
    remote peer may force the vulnerable QUIC stack to allocate 100MB of heap per connection. FIPS impact: no
    The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.
    (CVE-2026-75804)

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-2026-75804");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-75804");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-75804");
  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:N/I:C/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:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-75804");

  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:"2026/09/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
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  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:14.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:6");
  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:edk2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:edk2-hwe");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:nodejs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:AAVMF");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:OVMF");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:compat-openssl11");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:mingw-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:mingw32-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:mingw64-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:mokutil");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:openssl-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:openssl-libs");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-ia32");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-x64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openssl");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:mingw64-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:mokutil");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:openssl-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:openssl-static");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:ovmf");
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  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-14", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-6", "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-22.04", "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-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-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "efi-shell-aa64"},
          {"reference": "efi-shell-aa64-hwe"},
          {"reference": "efi-shell-loongarch64"},
          {"reference": "efi-shell-loongarch64-hwe"},
          {"reference": "efi-shell-riscv64"},
          {"reference": "efi-shell-riscv64-hwe"},
          {"reference": "efi-shell-x64"},
          {"reference": "efi-shell-x64-hwe"},
          {"reference": "ovmf"},
          {"reference": "ovmf-amdsev"},
          {"reference": "ovmf-amdsev-hwe"},
          {"reference": "ovmf-generic"},
          {"reference": "ovmf-generic-hwe"},
          {"reference": "ovmf-hwe"},
          {"reference": "ovmf-inteltdx"},
          {"reference": "ovmf-inteltdx-hwe"},
          {"reference": "ovmf-legacy"},
          {"reference": "ovmf-legacy-hwe"},
          {"reference": "qemu-efi-aarch64"},
          {"reference": "qemu-efi-aarch64-hwe"},
          {"reference": "qemu-efi-loongarch64"},
          {"reference": "qemu-efi-loongarch64-hwe"},
          {"reference": "qemu-efi-riscv64"},
          {"reference": "qemu-efi-riscv64-hwe"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "mokutil"},
          {"reference": "openssl"},
          {"reference": "openssl-devel"},
          {"reference": "openssl-libs"},
          {"reference": "openssl-perl"},
          {"reference": "shim-aa64"},
          {"reference": "shim-unsigned-aarch64"},
          {"reference": "shim-unsigned-x64"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-6": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "6",
        "pkgs": [
          {"reference": "openssl"},
          {"reference": "openssl-devel"},
          {"reference": "openssl-perl"},
          {"reference": "openssl-static"}
        ]
      }
    ]
  },
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "AAVMF"},
          {"reference": "OVMF"},
          {"reference": "mokutil"},
          {"reference": "openssl"},
          {"reference": "openssl-devel"},
          {"reference": "openssl-libs"},
          {"reference": "openssl-perl"},
          {"reference": "openssl-static"},
          {"reference": "ovmf"},
          {"reference": "shim"},
          {"reference": "shim-ia32"},
          {"reference": "shim-signed"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "AAVMF"},
          {"reference": "OVMF"},
          {"reference": "mokutil"},
          {"reference": "openssl"},
          {"reference": "openssl-devel"},
          {"reference": "openssl-libs"},
          {"reference": "openssl-perl"},
          {"reference": "openssl-static"},
          {"reference": "ovmf"},
          {"reference": "shim"},
          {"reference": "shim-ia32"},
          {"reference": "shim-signed"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "mingw-openssl"},
          {"reference": "mingw32-openssl"},
          {"reference": "mingw64-openssl"},
          {"reference": "shim"},
          {"reference": "shim-aa64"},
          {"reference": "shim-ia32"},
          {"reference": "shim-unsigned-aarch64"},
          {"reference": "shim-unsigned-x64"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "mingw-openssl"},
          {"reference": "mingw32-openssl"},
          {"reference": "mingw64-openssl"},
          {"reference": "shim"},
          {"reference": "shim-aa64"},
          {"reference": "shim-ia32"},
          {"reference": "shim-unsigned-aarch64"},
          {"reference": "shim-unsigned-x64"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "compat-openssl11"},
          {"reference": "openssl"},
          {"reference": "openssl-devel"},
          {"reference": "openssl-libs"},
          {"reference": "openssl-perl"},
          {"reference": "shim"},
          {"reference": "shim-aa64"},
          {"reference": "shim-unsigned-aarch64"},
          {"reference": "shim-unsigned-x64"},
          {"reference": "shim-x64"}
        ]
      }
    ]
  }
};

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 third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

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